LED module having LED chips as light source

ABSTRACT

An LED (Light Emitting Diode) module includes an LED unit having one or more LED chips and a case. The case includes: a body including a base plate made of ceramic, the base plate having a main surface and a bottom surface opposite to the main surface; a through conductor penetrating through the base plate; and one or more pads formed on the main surface and making conductive connection with the through conductor, the pads mounting thereon the LED unit. The through conductor includes a main surface exposed portion exposed to the main surface and overlapping the LED unit when viewed from top, a bottom surface reaching portion connected to the main surface exposed portion and reaching the bottom surface. The pads cover at least a portion of the main surface exposed portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2011-104923, filed on May 10, 2011,Japanese Patent Application No. 2011-136041, filed on Jun. 20, 2011,Japanese Patent Application No. 2011-132985, filed on Jun. 15, 2011, andJapanese Patent Application No. 2011-133598, filed on Jun. 15, 2011, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an LED (Light Emitting Diode) modulehaving an LED chip as a light source and a method for manufacturing thesame.

BACKGROUND

In recent years, LED modules have been employed as light sources forillumination apparatuses.

FIG. 75 shows one example of a conventional LED module. As shown in FIG.75, an LED module 900 a includes a rectangular substrate 910 made ofglass epoxy resin, and three LED chips 931, 932 and 933 mounted on thesubstrate 910. A plurality of electrodes 921, 922, 923 and 924 is formedon the substrate 910. The LED chips 931, 932 and 933 are die-bonded tothe electrodes 921, 922 and 923, respectively. The electrode 924 is aso-called common electrode and makes conductive connection with the LEDchips 931, 932 and 933 via wires 940. The three LED chips 931, 932 and933 are surrounded by a case 950. The case 950 is a frame-like opaqueresin material and has its inner space filled with transparent resin(not shown). The LED module 900 a is configured as a side view type LEDmodule that is mounted on a circuit board or the like, with a lowersurface extending in the longitudinal direction of the substrate 910 asa mounting surface. The LED chips 931, 932 and 933 emit red, green andblue light, respectively. The LED module 900 a aims to emit white lightby mixing the lights emitted from the LED chips 931, 932 and 933.

The LED module 900 is required to emit light with high luminance becauseit may be used as an illumination light source for a variety ofelectronic devices. However, the LED chips 931, 932 and 933 generateheat due to their emission. If this heat increases the temperature ofthe substrate 910 excessively, the substrate 910 made of glass epoxyresin is likely to be unduly deformed.

Recently, it has been increasingly required that an LED module emitlight close to natural light for illumination of a room. This recenttrend results in LED modules configured to emit white light.

FIG. 76 shows one example of a conventional LED module configured toemit white light. As shown in FIG. 76, an LED module 900 b includes asubstrate 91 made of glass epoxy resin, and an LED chip 92 mounted onthe substrate 91. A case 93 is attached to the substrate 91. The case 93has an opening 935 formed to expose the LED chip 92. The LED module 900b further includes a fluorescent resin 94 with which the opening 935 isfilled. In addition, a lens member 95 to cover the fluorescent resin 94is attached to the case 93.

The LED chip 92 is configured to emit, for example, blue light. Thefluorescent resin 94 emits yellow light by absorbing blue light emittedfrom the LED chip 92. The LED module 900 b emits white light by mixingthe blue light and the yellow light.

The color temperature of the white light emitted from the LED module 900b is determined by the LED chip 92 and the fluorescent resin 94. Thecolor temperature is an index indicating a relative strength between theblue-violet light and red light in the white light. A higher colortemperature provides more blue-violet light, whereas a lower colortemperature provides more red light. The color temperature of the whitelight may be varied by changing the ingredients of the fluorescent resin94. There is a need to provide the fluorescent resin 94 that is able toobtain light having a color temperature according to a consumer's taste.

Further, there is a need for mass production of the fluorescent resin 94in order to reduce the production costs of the LED module 900 b.Therefore, the manufacturability of the fluorescent resin 94 is limitedby material price and the amount of material available. Accordingly, itis not necessarily the case that a fluorescent resin capable ofobtaining light having a color temperature according to a consumer'staste can be easily produced.

FIG. 77 shows another example of a conventional LED module. As shown inFIG. 77, an LED module 900 c includes a substrate 901 and an LED chip902 mounted on the substrate 901. A frame-like reflector 905 is formedon the substrate 901. The reflector 905 has a reflecting surface 906surrounding the LED chip 902. The space surrounded by the reflectingsurface 906 is filled with a sealing resin 907. The LED chip 902includes a submount substrate 903 made of Si and a semiconductor layer904 stacked on the submount substrate 903. The semiconductor layer 904makes conductive connection with the substrate 901 via the submountsubstrate 903.

There is a strong need for compactness of the LED module 900 c. Tofacilitate reduction of the size of the LED module 900 c, the angle ofthe reflecting surface 906 needs to be adjusted to follow the verticaldirection in FIG. 77. As the reflecting surface 906 is adjusted to bealigned with the vertical direction, light emitted from the LED chip 902toward the reflecting surface 906 propagates in the sealing resin 907 atan angle closer to the horizontal direction after being reflected by thereflecting surface 906. This light is likely to be completely reflectedon the top side of the sealing resin 907.

LED modules containing LED chips that are capable of emitting whitelight are widely used for light sources of a variety of electronics. AnLED module capable of emitting white light includes, for example, an LEDchip which emits blue light and a fluorescent portion which covers theLED chip. The fluorescent portion is obtained by mixing fluorescentmaterial in transparent resin. Examples of the fluorescent material mayinclude red fluorescent material which emits red light when it isexcited by blue light, green fluorescent material which emits greenlight when it is excited by blue light, and a combination thereof. Whenthe blue light, the red light and the green light are mixed together,white light is emitted from the LED module.

Depending on the application of an LED module, it may be important toreproduce the inherent tone of an illuminated object. This colorrendering property is commonly estimated by using an average colorrendering index (hereinafter, referred to as “Ra value”) defined by JIS(Japanese Industrial Standards). A simple mixture of blue light, redlight and green light may not necessarily provide a sufficient Ra value.Applications placing stress on the color rendering property require anLED module having an Ra value as large as possible.

SUMMARY

The present disclosure provides some embodiments of an LED module whichis capable of achieving high luminance and high heat radiation.

Further, the present disclosure provides some embodiments of an LEDmodule which is capable of providing light having a more preferablecolor temperature.

Further, the present disclosure provides some embodiments of an LEDmodule which is capable of achieving compactness and high luminance.

Further, the present disclosure provides some embodiments of an LEDmodule which is capable of increasing an Ra value and a method ofmanufacturing the same.

According to one aspect of the present disclosure, there is provided anLED module including an LED unit having one or more LED chips and acase. The case includes: a body including a base plate made of ceramic,the base plate having a main surface and a bottom surface opposite tothe main surface; a through conductor penetrating through the baseplate: and one or more pads formed on the main surface and makingconductive connection with the through conductor, the pads mountingthereon the LED unit. The through conductor may have a main surfaceexposed portion exposed to the main surface and overlapping the LED unitwhen viewed from top, and a bottom surface reaching portion connected tothe main surface exposed portion and reaching the bottom surface, thebottom surface reaching portion not overlapping the LED unit when viewedfrom top. The pads may cover at least a portion of the main surfaceexposed portion.

In some embodiments, the main surface exposed portion contains the LEDunit when viewed from top.

In some embodiments, at least a portion of the bottom surface reachingportion does not overlap the LED unit.

In some embodiments, the pads cover the main surface exposed portionsuch that the main surface exposed portion is not exposed.

In some embodiments, the through conductor is made of Ag.

In some embodiments, each of the pads has a surface made of Au.

In some embodiments, a mounting electrode making a conductive connectionwith the through conductor is formed on the bottom surface of the baseplate.

In some embodiments, the body further includes a frame unit made ofresin, the frame unit being bonded to the main surface and surroundingthe LED unit.

In some embodiments, an inner side of the frame unit surrounding the LEDunit serves as a reflector.

In some embodiments, the reflector has a section perpendicular to anormal line of the main surface, a dimension of the section decreasingas the section becomes more spaced apart from the main surface.

In some embodiments, the LED module further includes a transparent resinfilling a region surrounded by the frame unit and covering the LED unit,the transparent resin being formed of resin material transmitting lightfrom the LED unit and fluorescent material emitting, when excited by thelight emitted from the LED unit, light having a wavelength differentfrom a wavelength of the light emitted from the LED unit.

With this configuration, heat generated from the LED unit can betransferred to the bottom surface of the case via the pads, the mainsurface exposed portion and the bottom surface reaching portion, whichresults in an improvement in heat radiation of the LED module.

According to another aspect of the present disclosure, there is providedan LED module including an LED unit having one or more LED chips and acase. The case may include one or more pads mounting thereon the LEDunit, a base plate having a main surface on which the pads are formedand a bottom surface opposite to the main surface, and a frame unitbonded to the main surface and surrounding the LED unit. The base platemay be made of ceramic and the frame unit may be made of resin.

In some embodiments, an inner side of the frame unit surrounds the LEDunit.

In some embodiments, the reflector has a section perpendicular to anormal line of the main surface, a dimension of the section decreasingas the section becomes more spaced apart from the main surface.

In some embodiments, the LED module further includes a transparent resinfilling a region surrounded by the frame unit and covering the LED unit,the transparent resin being formed of a resin material transmittinglight emitted from the LED unit and fluorescent material emitting, whenexcited by the light emitted from the LED unit, light having awavelength different from a wavelength of the light emitted from the LEDunit.

In some embodiments, the case further includes a through conductormaking conductive connection with the pads and penetrating through thebase plate, the through conductor having a main surface exposed portionexposed to the main surface and overlapping the LED unit when viewedfrom top, and a bottom surface reaching portion connected to the mainsurface exposed portion and reaching the bottom surface. The bottomsurface reaching portion does not overlap with the LED unit when viewedfrom top. The pads cover at least a portion of the main surface exposedportion.

In some embodiments, the main surface exposed portion contains the LEDunit when viewed from top.

In some embodiments, at least a portion of the bottom surface reachingportion does not overlap the LED unit.

In some embodiments, the pads cover the main surface exposed portionsuch that the main surface exposed portion is not exposed.

In some embodiments, the through conductor is made of Ag.

In some embodiments, each of the pads has a surface made of Au.

In some embodiments, a mounting electrode making a conductive connectionwith the through conductor is formed on the bottom surface of the baseplate.

With this configuration, heat generated from the LED unit can betransferred to the bottom surface of the case via the pads, the mainsurface exposed portion and the bottom surface reaching portion, whichresults in an improvement in heat radiation of the LED module.

Further, since the ceramic is not noticeably thermally-deformed becauseof its relatively low thermal expansion, the case can be prevented frombecoming unduly deformed even if the LED module is designed to have highluminance, where the amount of heat generated from the LED unit tends toincrease. Furthermore, very little heat generated from the LED unit istransferred to the frame unit. This reduces the likelihood of producingexcessive thermal deformation, even if the frame unit is made of resin.Furthermore, the resin of which the frame unit is made is higher inreflectivity than ceramic. This facilitates the achievement of highluminance of the LED module.

According to another aspect of the present disclosure, there is providedan LED module including a first LED chip, a first fluorescent resincovering the first LED chip and a case supporting the first fluorescentresin. The first fluorescent resin may generate a first fluorescentlight when excited by light from the first LED chip, and light having afirst color temperature may be emitted when the light from the first LEDchip is mixed with the first fluorescent light. The LED module mayfurther include a second LED chip and a second fluorescent resincovering the second LED chip. The second fluorescent resin may generatea second fluorescent light when excited by light from the second LEDchip, and light having a second color temperature different from thefirst color temperature may be emitted when the light from the secondLED chip is mixed with the second fluorescent light.

With this configuration, by emitting light having the first colortemperature and light having the second color temperaturesimultaneously, light having a color temperature between the first andthe second color temperature can be provided. Accordingly, the LEDmodule of the present disclosure can provide light having a colortemperature which is difficult to obtain by conventional LED modulesemitting light having a single color temperature, by mixing lightshaving two or more color temperatures. Accordingly, the presentdisclosure can provide light having a more preferable color temperaturewhich cannot be provided by conventional LED modules.

In some embodiments, the case has a first opening exposing the first LEDchip and a second opening exposing the second LED chip, and the firstfluorescent resin fills the first opening and the second fluorescentresin fills the second opening.

In some embodiments, the case includes a base plate having a mainsurface and a bottom surface opposite to the main surface, and a frameunit in which the first and the second opening are formed. The first andthe second LED chip may be disposed on the main surface, and the frameunit may be arranged such that the first and the second opening exposethe main surface.

In some embodiments, the frame unit includes an outer frame and apartition formed inside the outer frame. The partition may be interposedbetween the first and the second opening in a first direction.

In some embodiments, the frame has a first inner side located at oneside of the partition in the first direction and a second inner sidelocated at the other side of the partition in the first direction, thepartition has a first side and a second side located at the other sideof the first side in the first direction, the first opening is definedby the first inner side and the first side, and the second opening isdefined by the second inner side and the second side.

In some embodiments, the first inner side is inclined in such a mannerthat it becomes farther away from the first LED unit in the firstdirection as it moves farther away from the main surface in a directionperpendicular to the main surface, and the second inner side is inclinedin such a manner that it becomes farther away from the second LED unitin the first direction as it moves farther away from the main surface inthe direction perpendicular to the main surface.

In some embodiments, the first side is inclined in such a manner that itbecomes closer to the main surface in the direction perpendicular to themain surface as it moves toward one side in the first direction, and thesecond side is inclined in such a manner that it becomes closer to themain surface in the direction perpendicular to the main surface as itmoves toward the other side in the first direction.

In some embodiments, each of the first LED chip and the second LED chipincludes a first electrode and a second electrode. The case may includea first mounting electrode making conductive connection with the firstelectrode of the first LED chip, a second mounting electrode makingconductive connection with the second electrode of the first LED chipand the second electrode of the second LED chip, and a third mountingelectrode making conductive connection with the first electrode of thesecond LED chip, and the first to third mounting electrodes may bespaced apart from each other.

In some embodiments, the second electrode of the second LED chip makesconductive connection with the second mounting electrode.

In some embodiments, the first to third mounting electrodes are disposedon the bottom surface.

In some embodiments, the second mounting electrode is interposed betweenthe first mounting electrode and the third mounting electrode in thefirst direction.

In some embodiments, the first mounting electrode is located at one sideof the second mounting electrode in the first direction, the thirdmounting electrode is located at the other side of the second mountingelectrode in the first direction, the second electrode of the first LEDchip is located at the other side of the first LED chip with respect tothe first electrode of the first LED chip in the first direction, andthe second electrode of the second LED chip is located at the other sideof the second LED chip with respect to the first electrode of the secondLED chip in the first direction.

In some embodiments, the case includes a first bonding pad disposed onthe main surface and covered by the first fluorescent resin and a secondbonding pad disposed on the main surface and covered by the secondfluorescent resin. The first bonding pad may be located at one side ofthe first LED chip in the first direction and make conductive connectionwith the first mounting electrode, and the second bonding pad may belocated at the other side of the second LED chip in the first directionand make conductive connection with the third mounting electrode. Thecase further includes a first wire making conductive connection betweenthe first electrode of the first LED chip and the first bonding pad, anda second wire making conductive connection between the first electrodeof the second LED chip and the second bonding pad.

In some embodiments, the LED unit further includes a first additionalLED chip covered by the first fluorescent resin and having a firstelectrode making conductive connection with the first mounting electrodeand a second electrode making conductive connection with the secondmounting electrode. The first additional LED chip may be disposed in aposition different from the first LED chip in the first direction anddifferent from the first LED chip in a second direction perpendicular tothe first direction.

In some embodiments, the LED unit further includes a second addition LEDchip covered by the second fluorescent resin and having a firstelectrode making conductive connection with the third mounting electrodeand a second electrode making conductive connection with the secondmounting electrode. The second additional LED chip may be disposed in aposition different from the second LED chip in the first direction anddifferent from the second LED chip in a second direction perpendicularto the first direction.

In some embodiments, the case includes a first bonding pad disposed onthe main surface and covered by the first fluorescent resin and a secondbonding pad disposed on the main surface and covered by the secondfluorescent resin. The first bonding pad may be located at one side ofthe first LED chip in the first direction and make conductive connectionwith the first mounting electrode, and the second bonding pad may belocated at the other side of the second LED chip in the first directionand make conductive connection with the third mounting electrode. Thecase may further include a first wire making a conductive connectionbetween the first electrode of the first LED chip and the first bondingpad, a first additional wire making a conductive connection between thefirst electrode of the first additional LED chip and the first bondingpad, a second wire making a conductive connection between the firstelectrode of the second LED chip and the second bonding pad, and asecond additional wire making a conductive connection between the firstelectrode of the second additional LED chip and the second bonding pad.

In some embodiments, the width of the partition in the first directionis smaller than that of the outer frame.

In some embodiments, the LED unit further includes a third LED chipdisposed on the main surface, and the case further includes a thirdopening exposing the third LED chip and a third fluorescent resinfilling the third opening.

In some embodiments, the frame unit includes an additional partitioninterposed between the second opening and the third opening in the firstdirection.

In some embodiments, the first color temperature is lower than thesecond color temperature, and the third fluorescent resin emits thefirst fluorescent light when excited by light from the third LED chip.

In some embodiments, the frame unit includes an additional partitioninterposed between the second opening and the third opening in a seconddirection perpendicular to the first direction.

In some embodiments, the first color temperature is lower than thesecond color temperature, and the third fluorescent resin emits thesecond fluorescent light when excited by light from the third LED chip.

In some embodiments, the LED unit further includes a fourth LED chipdisposed on the main surface, and the case further includes a fourthopening exposing the fourth LED chip and a fourth fluorescent resinfilling the fourth opening. The partition may be interposed between thethird opening and the fourth opening in the first direction, and theframe unit may include an additional partition interposed between thefirst opening and the fourth opening in the second directionperpendicular to the first direction.

According to another aspect of the present disclosure, there is providedan LED module including one or more LED chips, a supporting membermounting thereon the LED chips and having a reflecting surfacesurrounding the LED chips, a sealing resin filling a space surrounded bythe reflecting surface and transmitting light from the LED chips. Thereflecting surface may have unevenness to scatter the light from the LEDchips.

In some embodiments, the reflecting surface is made of resin.

In some embodiments, the resin is white.

In some embodiments, the roughness of the reflecting surface is 1 μm to10 μm in Ry (maximum height).

In some embodiments, the supporting member includes a substrate having abase and a wiring pattern and mounting thereon the LED chips and areflector formed on the substrate and having the reflecting surface.

In some embodiments, the supporting member includes a plurality of leadsmounting thereon the LED chips and a reflector having the reflectingsurface and covering some of the leads.

In some embodiments, each of the LED chips includes a submount substratemade of Si and a semiconductor layer stacked on the submount substrate.

In some embodiments, the LED module further includes two wiresconnecting the submount substrate and the supporting member.

In some embodiments, the LED module further includes one wire connectingthe submount substrate and the supporting member.

In some embodiments, two electrode pads are formed on a surface of thesubmount substrate, the surface opposite to a surface on which thesemiconductor layer is stacked, and the two electrodes are bonded to andmake conductive connection with the supporting member.

In some embodiments, each of the LED chips includes two electrode padsbonded to the semiconductor layer and the supporting member.

In some embodiments, a surface of the semiconductor layer opposite tothe supporting member includes an uneven surface.

In some embodiments, the roughness of the uneven surface of thesemiconductor layer is 1 μm to 10 μm in Ry (maximum height).

In some embodiments, the semiconductor layer emits blue light or greenlight.

In some embodiments, mixed in the sealing resin is fluorescent materialemitting light having a wavelength different from a wavelength of lightfrom the LED chips when the sealing resin is excited by the light fromthe LED chips.

In some embodiments, the fluorescent material emits yellow light.

With this configuration, light propagating within the LED chips to thereflecting surface is scattered by the reflecting surface. The scatteredlight includes light having an incidence angle smaller than a criticalangle to the top side of the sealing resin and is not totally reflected.This facilitates reliable emission of some light propagating onto thereflecting surface from the sealing resin, which results in compactnessand high luminance of the LED module.

According to another aspect of the present disclosure, there is providedan LED module emitting white light, the LED module including asemiconductor light emitting device having an output peak wavelength of440 nm to 485 nm and a fluorescent portion having a first and a secondfluorescent material disposed to receive light from the semiconductorlight emitting device. When the fluorescent portion is excited by thelight from the semiconductor light emitting device, the firstfluorescent material emits light having a peak wavelength equal to orgreater than 655 nm and the second fluorescent material emits lighthaving a peak wavelength equal to or less than 565 nm.

In some embodiments, the peak wavelength of the light emitted from thefirst fluorescent material is equal to or less than 700 nm and the peakwavelength of the light emitted from the second fluorescent material isequal to or greater than 500 nm.

In some embodiments, the peak wavelength of the light emitted from thesecond fluorescent material is equal to or less than 525 nm.

In some embodiments, a mixture ratio of the second fluorescent materialto the first fluorescent material is 5.5 to 7.0.

According to another aspect of the present disclosure, there is providedan LED module emitting white light, the LED module including asemiconductor light emitting device having an output peak wavelength of440 nm to 485 nm and a fluorescent portion having a first and a secondfluorescent material disposed to receive light from the semiconductorlight emitting device. When the fluorescent portion is excited by thelight from the semiconductor light emitting device, the firstfluorescent material emits light having a peak wavelength equal to orgreater than 625 nm and the second fluorescent material emits lighthaving a peak wavelength equal to or less than 520 nm.

In some embodiments, the peak wavelength of the light emitted from thefirst fluorescent material is equal to or less than 700 nm and the peakwavelength of the light emitted from the second fluorescent material isequal to or greater than 500 nm.

In some embodiments, the peak wavelength of the light emitted from thefirst fluorescent material is equal to or greater than 645 nm.

In some embodiments, the output peak wavelength of the semiconductorlight emitting device is 445 nm to 465 nm.

In some embodiments, a mixture ratio of the second fluorescent materialto the first fluorescent material is 5.0 to 6.5.

According to another aspect of the present disclosure, there is providedan LED module emitting white light, the LED module including asemiconductor light emitting device having an output peak wavelength of440 nm to 485 nm and a fluorescent portion having a first and a secondfluorescent material disposed to receive light from the semiconductorlight emitting device. When the fluorescent portion is excited by thelight from the semiconductor light emitting device, the firstfluorescent material emits light having a peak wavelength equal to orgreater than 625 nm and the second fluorescent material emits lighthaving a peak wavelength equal to or less than 565 nm, wherein adifference in the peak wavelengths between the light from the firstfluorescent material and the light from the second fluorescent materialis equal to or greater than 120 nm.

In some embodiments, the peak wavelength of the light emitted from thefirst fluorescent material is equal to or less than 700 nm and the peakwavelength of the light emitted from the second fluorescent material isequal to or greater than 500 nm.

In some embodiments, a mixture ratio of the second fluorescent materialto the first fluorescent material is 5.0 to 7.5.

In some embodiments, the output peak wavelength of the semiconductorlight emitting device is 445 nm to 465 nm.

According to another aspect of the present disclosure, there is providedan LED module emitting white light, the LED module including asemiconductor light emitting device having an output peak wavelength of440 nm to 485 nm and a fluorescent portion having a first and a secondfluorescent material disposed to receive light from the semiconductorlight emitting device. When the fluorescent portion is excited by thelight from the semiconductor light emitting device, the firstfluorescent material emits light having a peak wavelength equal to orgreater than 625 nm and the second fluorescent material emits lighthaving a peak wavelength equal to or less than 565 nm, wherein a mixtureratio of the second fluorescent material to the first fluorescentmaterial is 6.8 to 7.2.

In some embodiments, the peak wavelength of the light emitted from thefirst fluorescent material is equal to or less than 645 nm

In some embodiments, the peak wavelength of the light emitted from thesecond fluorescent material is equal to or greater than 530 nm.

According to another aspect of the present disclosure, there is providedan LED module emitting white light, the LED including a semiconductorlight emitting device having an output peak wavelength of 440 nm to 485nm and a fluorescent portion having a first and a second fluorescentmaterial disposed to receive light from the semiconductor light emittingdevice. When the fluorescent portion is excited by the light from thesemiconductor light emitting device, the first fluorescent materialemits light having a peak wavelength of 640 nm to 675 nm and the secondfluorescent material emits light having a peak wavelength of 500 nm to535 nm, wherein a mixture ratio of the second fluorescent material tothe first fluorescent material is 5.0 to 7.5.

In some embodiments, the output peak wavelength of the semiconductorlight emitting device is 440 nm to 470 nm, the peak wavelength of thelight emitted from the first fluorescent material is 640 nm to 655 nm,the peak wavelength of the light emitted from the second fluorescentmaterial is 520 nm to 530 nm, and the mixture ratio of the secondfluorescent material to the first fluorescent material is 6.5 to 7.5.

In some embodiments, the output peak wavelength of the semiconductorlight emitting device is 440 nm to 470 nm, the peak wavelength of thelight emitted from the first fluorescent material is 645 nm to 655 nm,and the mixture ratio of the second fluorescent material to the firstfluorescent material is 5.5 to 7.5.

In some embodiments, the output peak wavelength of the semiconductorlight emitting device is 440 nm to 470 nm, the peak wavelength of thelight emitted from the second fluorescent material is 520 nm to 530 nm,and the mixture ratio of the second fluorescent material to the firstfluorescent material is 5.5 to 7.5.

In some embodiments, the output peak wavelength of the semiconductorlight emitting device is 440 nm to 470 nm, the peak wavelength of thelight emitted from the first fluorescent material is 645 nm to 655 nm,and the peak wavelength of the light emitted from the second fluorescentmaterial is 520 nm to 530 nm.

In some embodiments, the first and the second fluorescent material areuniformly distributed in the fluorescent portion.

With this configuration, an Ra value of light emitted from the LEDmodule can be increased and the LED mode suitable for applicationsplacing stress on color rendition can be provided.

These and other features and advantages of the present disclosure areapparent from the following detailed description in conjunction with theaccompanying, drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing an LED module according to a firstembodiment of the present disclosure.

FIG. 2 is a sectional view taken along line II-II in FIG. 1.

FIG. 3 is a sectional view taken along line III-III in FIG. 1.

FIG. 4 is a main part enlarged sectional view showing the LED moduleaccording to the first embodiment of the present disclosure.

FIG. 5 is a main part enlarged plan view showing the LED moduleaccording to the first embodiment of the present disclosure.

FIG. 6 is a bottom view showing the LED module according to the firstembodiment of the present disclosure.

FIG. 7 is a plan view showing an LED module according to a secondembodiment of the present disclosure.

FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7.

FIG. 9 is a sectional view taken along line IX-IX in FIG. 7.

FIG. 10 is a main part enlarged sectional view showing the LED moduleaccording to the second embodiment of the present disclosure.

FIG. 11 is a plan view showing an LED module according to a thirdembodiment of the present disclosure.

FIG. 12 is a sectional view taken along line XII-XII in FIG. 11.

FIG. 13 is a sectional view taken along line XIII-XIII in FIG. 11.

FIG. 14 is a main pan enlarged sectional view showing the LED moduleaccording to the third embodiment of the present disclosure.

FIG. 15 is a plan view showing an LED module according to a fourthembodiment of the present disclosure.

FIG. 16 is a sectional view taken along line XVI-XVI in FIG. 15.

FIG. 17 is a sectional view taken along line XVII-XVII in FIG. 15.

FIG. 18 is a main part enlarged sectional view showing the LED moduleaccording to the fourth embodiment of the present disclosure.

FIG. 19 is a main part enlarged sectional view showing an LED moduleaccording to a fifth embodiment of the present disclosure.

FIG. 20 is a main part enlarged plan view showing the LED moduleaccording to the fifth embodiment of the present disclosure.

FIG. 21 is a sectional view showing an LED module according to a sixthembodiment of the present disclosure.

FIG. 22 is a sectional view showing an LED module according to a seventhembodiment of the present disclosure.

FIG. 23 is a perspective view showing an LED module according to aneighth embodiment of the present disclosure.

FIG. 24 is a main part plan view of the LED module shown in FIG. 23.

FIG. 25 is a bottom view of the LED module shown in FIG. 23.

FIG. 26 is a sectional view taken along line IV-IV in FIG. 24.

FIG. 27 is a sectional view taken along line V-V in FIG. 24.

FIG. 28 is a main part enlarged sectional view showing the LED unit in afirst opening shown in FIG. 26.

FIG. 29 is a main part enlarged sectional view showing the LED unit in asecond opening shown in FIG. 26.

FIG. 30 is a main part plan view of the LED unit shown in FIG. 28.

FIG. 31 is a main part plan view showing an LED module according to aninth embodiment of the present disclosure.

FIG. 32 is a sectional view taken along line X-X in FIG. 31.

FIG. 33 is a sectional view taken along line XI-XI in FIG. 31.

FIG. 34 is a main part enlarged sectional view showing the LED unit in afirst opening shown in FIG. 32.

FIG. 35 is a main part plan view showing an LED module according to atenth embodiment of the present disclosure.

FIG. 36 is a sectional view taken along line XIV-XIV in FIG. 35.

FIG. 37 is a sectional view taken along line XV-XV in FIG. 35.

FIG. 38 is a main part enlarged sectional view showing an LED moduleaccording to an 11th embodiment of the present disclosure.

FIG. 39 is a main part plan view showing an LED module according to a12th embodiment of the present disclosure.

FIG. 40 is a bottom view of the LED module shown in FIG. 39.

FIG. 41 is a sectional view taken along line XIX-XIX in FIG. 39.

FIG. 42 is a sectional view taken along line XX-XX in FIG. 39.

FIG. 43 is a plan view showing an LED module according to a 13thembodiment of the present disclosure.

FIG. 44 is a main part plan view of the LED module shown in FIG. 43.

FIG. 45 is a bottom view of the LED module shown in FIG. 43.

FIG. 46 is a plan view showing an LED module according to a 14thembodiment of the present disclosure.

FIG. 47 is a main part plan view of the LED module shown in FIG. 46.

FIG. 48 is a bottom view of the LED module shown in FIG. 46.

FIG. 49 is a perspective view showing an LED module according to a 15thembodiment of the present disclosure.

FIG. 50 is a plan view showing the LED module shown in FIG. 49.

FIG. 51 is a sectional view taken along line III-III in FIG. 50.

FIG. 52 is a main part enlarged sectional view showing the LED moduleshown in FIG. 1.

FIG. 53 is a plan view showing an LED module according to a 16thembodiment of the present disclosure.

FIG. 54 is a sectional view taken along line VI-VI in FIG. 53.

FIG. 55 is a main part enlarged sectional view showing the LED moduleshown in FIG. 53.

FIG. 56 is a plan view showing an LED module according to a 17thembodiment of the present disclosure.

FIG. 57 is a sectional view taken along line IX-IX in FIG. 56.

FIG. 58 is a main part enlarged sectional view showing the LED moduleshown in FIG. 56.

FIG. 59 is a main part enlarged sectional view showing a modification ofthe LED chip in the LED module shown in FIG. 56.

FIG. 60 is a perspective view showing an LED module according to an 18thembodiment of the present disclosure.

FIG. 61 is a plan view showing the LED module shown in FIG. 60.

FIG. 62 is a sectional view taken along line XIV-XIV in FIG. 61.

FIG. 63 is a sectional view showing an LED module according to a 19thembodiment of the present disclosure.

FIG. 64 is a sectional view showing an LED module according to a 20thembodiment of the present disclosure.

FIG. 65 is a plan view showing an LED module according to a 21stembodiment of the present disclosure.

FIG. 66 is a bottom view of the LED module shown in FIG. 65.

FIG. 67 is a sectional view taken along line XIX-XIX in FIG. 65.

FIG. 68 is a sectional view taken along line XX-XX in FIG. 65.

FIG. 69 is a plan view showing an LED module according to a 22ndembodiment of the present disclosure.

FIG. 70 is a sectional view taken along line XXII-XXII in FIG. 69.

FIG. 71 is a sectional view taken along line XXIII-XXIII in FIG. 69.

FIG. 72 is a sectional view showing an LED module according to a 23rdembodiment of the present disclosure.

FIG. 73 is a table of the 23rd embodiment of the present disclosure,showing a relationship between a peak wavelength of a light emittingdevice, peak wavelengths of red fluorescent material and greenfluorescent material, and an Ra value.

FIG. 74 is a graph showing an emission spectrum of the LED moduleaccording to the 23rd embodiment of the present disclosure.

FIG. 75 is a sectional view showing one example of a conventional LEDmodule.

FIG. 76 is a sectional view showing one example of a conventional LEDmodule.

FIG. 77 is a sectional view showing one example of a conventional LEDmodule.

DETAILED DESCRIPTION

Preferred embodiments of the present disclosure will now be described indetail with reference to the drawings.

First, LED modules which are capable of achieving high luminance andhigh heat radiation will be described in detail with reference to FIGS.1 to 22.

FIGS. 1 to 6 show one example of an LED module according to anembodiment of the present disclosure. In this embodiment, an LED moduleA1 includes a case 1, a plurality of LED units 2, a zener diode 33,wires 3 and transparent resin 5 (not shown in FIG. 1). The LED module A1is a high power type LED module having relatively high luminance and hasthe dimensions of a square of 5 mm×5 mm and a thickness of about 0.9 mmwhen viewed from top.

The case 1 includes a body 10, a plurality of pads 13 a and 13 b, aplurality of bonding pads 14 a and 14 b, a pad 33 a, a pair of mountingelectrodes 150 a and 150 b and a plurality of through conductors 15 a,15 b, 15 c and 15 d.

The body 10 includes a base plate 11 and a frame unit 12. The base plate11 is of a rectangular plate shape and is made of a white ceramic suchas alumina or the like. The base plate 11 has a main surface 111 and abottom surface 112. The frame unit 12 is bonded to the main surface 111of the base plate 11 and has a frame shape when viewed from top. Theframe unit 12 is made of a white resin such as epoxy resin, siliconeresin, liquid crystal polymer (LCP), polyphthalamide (PPA) or the like,which is higher in reflectivity than ceramic. An inner side of the frameunit 12 corresponds to a reflector 120. The reflector 120 reflectslight, which propagates from a plurality of LED chips 21 in theleft/right direction in FIG. 2, into the upper side of FIG. 2. Thereflector 120 is tapered in such a manner that the dimensions of asection perpendicular to the normal line of the main surface 111decreases as the reflector 120 is farther away from the main surface111. In this embodiment, the reflector 120 is formed with four concaveportions 120 a. Each of the four concave portions 120 a has a sectionalshape which is substantially triangular when viewed from top, andextends to reach the main surface 111. The main surface 111 issubstantially circular and is connected to a bottom edge of thereflector 120.

The plurality of pads 13 a and 13 b (three pads 13 a and three pads 13 bin this embodiment) is arranged in two lines on the main surface 111.Each of the pads 13 a and 13 b has a rectangular shape and is formed ofa plating layer made of, for example, Ni and Au stacked in order fromthe main surface 111. If the top surface of the plating layer is made ofAu, the thickness oldie Au layer may be about 0.1 μm.

The plurality of bonding pads 14 a and 14 b (three bonding pads 14 a andthree bonding pads 14 b in this embodiment) is arranged in two columnson the main surface 111. Each of the bonding pads 14 a and 14 b has arectangular shape and has the same plating structure as that of the pads13 a and 13 b. About one-third of the area of the bonding pads 14 a and14 b located at four corners is accommodated in the four concaveportions 120 a.

The pad 33 a is disposed near an edge of the main surface 111 and hasthe same plating structure as that of the pads 13 a and 13 b and thebonding pads 14 a and 14 b.

As shown in FIG. 6, the pair of mounting electrodes 150 a and 150 b isformed on the bottom Surface 112, opposite to the side where thereflector 120 and the main surface 111 are formed in the body 10, andhas a rectangular shape. In FIG. 6, the mounting electrode 150 a isparticularly larger than the mounting electrode 150 b and overlaps theplurality of LED chips 21 when viewed from top.

The through conductors 15 a, 15 b, 15 c and 15 d pass through the body10 and are made of for example, Ag or W. In this embodiment, threethrough conductors 15 a connect the three bonding pads 14 a and themounting electrode 150 a. Three through conductors 15 b connect thethree pads 13 a and the mounting electrode 150 a. Three throughconductors 15 c connect the three pads 13 b and the mounting electrode150 a. One through conductor 15 c connects the pad 33 a and the mountingelectrode 150 a. Three through conductors 15 d connect the three bondingpads 14 b and the mounting electrode 150 b, and are formed in a crankshape.

The through conductors 15 b and 15 c include main surface exposedportions 151 b and 151 c and bottom surface reaching portions 152 b and152 c, respectively. As shown in FIGS. 2 and 3, the main surface exposedportions 151 b and 151 c are exposed to the main surface 111 and have aplate shape whose dimension is relatively small in the thicknessdirection of the base plate 11 but relatively large when viewed fromtop. The bottom surface reaching portions 152 b and 152 c are connectedto the bottom surfaces of the main surface exposed portions 151 b and151 c, respectively, and their bottoms reach the bottom surface 112. Thebottom surface reaching portions 152 b and 152 c have a cylindricalshape whose dimension is relatively small in the thickness direction ofthe base plate 11 and relatively small when viewed from top. In thisembodiment, the main surface exposed portions 151 b and 151 c are largerthan the LED unit 2 when viewed from top and contain the LED unit 2 whenviewed from top. In addition, the bottom surface reaching portions 152 band 152 c are deviated from the LED unit 2 when viewed from top.

The base plate 11 and the through conductors 15 a, 15 b, 15 c and 15 dmay be formed for example, by firing a ceramic material and Ag or Wmaterial, which are stacked in appropriate order. The pads 13 a and 13b, the bonding pads 14 a and 14 b, and the mounting electrodes 150 a and150 b may be formed by plating with respect to the base plate 11. Inaddition, the case 1 may be obtained by bonding the frame unit 12 madeof resin to the base plate 11.

In this embodiment, the main surface exposed portion 151 b is entirelycovered by the pad 13 a and the main surface exposed portion 151 c isentirely covered by the pad 13 b. As shown in FIG. 4, a portion of theupper side of the main surface exposed portion 151 b overlapping thebottom surface reaching portion 152 b when viewed from top has a cavedshape, and a portion of the pad 13 a overlapping the portion oldie upperside of the main surface exposed portion 151 b also has a caved shape.It is believed that the caved shapes result from the remains of a cavedliquid level of liquefied Ag or W material during a firing step in themanufacturing process of the case 1. In addition, since the pad 13 a isformed by plating, the upper side of the pad 13 a has a caved shapeaccording to the cave formed in the through conductor 15 b. This isequally applied to the main surface exposed portion 151 c and the bottomsurface reaching portion 152 c.

The plurality of LED units 2 serves as a light source of the LED moduleA1 and includes a plurality of LED chips 21 in this embodiment. Each ofthe LED chips 21 includes an n-type semiconductor layer made of, forexample, a GaN semiconductor, a p-type semiconductor layer made of, forexample, a GaN semiconductor, and an active layer interposedtherebetween; and emits blue light. Each of the LED chips 21 iseutectically bonded to the pads 13 a and 13 b. When viewed from top, thedimensions of each of the LED chips 21 is smaller than the dimensions ofthe pads 13 a and 13 b. That is, the outer edges of the pads 13 a and 13b when viewed from top are located a little outside of the outer edgesof each of the LED chips 21. In this embodiment, each of the LED chips21 is a so-called 2-wire type LED chip.

The zener diode 33 serves to prevent an excessive reverse voltage frombeing applied to the plurality of LED chips 21 and acts to flow areverse current only when a reverse voltage exceeding a predeterminedvoltage is applied. The zener diode 33 is bonded to the pad 33 a via,for example, Ag paste.

The plurality of wires 3 is made of, for example, Au and has one endbonded to the bonding pads 14 a and 14 b and the other end bonded to theLED chip 21 or the zener diode 33.

A region surrounded by the reflector 120 and the main surface 111 isfilled with the transparent resin 5 to cover the plurality of LED chips21, the zener diode 33 and the plurality of wires 3. The transparentresin 5 is made of, for example, a mixture of transparent silicone resinand fluorescent material. The fluorescent material emits yellow light,for example, when it is excited by the blue light from the LED chips 21.When the yellow light is mixed with the blue light from the LED chips21, white light is emitted from the LED module A1. Alternatives to theabove-mentioned fluorescent material may include a fluorescent materialemitting red light and a fluorescent material emitting green light whenthey are excited by the blue light.

Next, operation of the LED module A1 will be described.

In this embodiment, the LED unit 2 is supported by the main surfaceexposed portions 151 b and 151 c via the pads 13 a and 13 b. Thisfacilitates the transfer of heat from the LED unit 2 to the bottomsurface 112 via the main surface exposed portions 151 b and 151 c andthe bottom surface reaching portions 152 b and 152 c, which may resultin high heat radiation of the LED module A1.

As shown in FIG. 4, the bottom surface reaching portions 152 b and 152 care likely to cause caves in the main surface exposed portions 151 b and151 c, respectively. In many cases, these caves may lead to caves in thesurfaces of the pads 13 a and 13 b. When the bottom surface exposedportions 152 b and 152 c are deviated from the LED unit 2 when viewedfrom top, the caves of the pads 13 a and 13 b are not covered by the LEDunit 2. This can prevent the LED unit 2 and the pads 13 a and 13 b fromhaving a gap therebetween.

The main surface exposed portions 151 b and 151 c are larger indimension than the bottom surface reaching portions 152 b and 152 c whenviewed from top. This reduces the likelihood of producing noticeablecaves. The main surface exposed portions 151 b and 151 c have a size andposition which enables the LED unit 2 to be contained thereon whenviewed from top, and the portions of the surfaces of the pads 13 a and13 b that overlap with the LED unit 2 to have a flat shape. Thisfacilitates stable mounting of the LED unit 2.

The base plate 11 made of ceramic is not noticeably thermally-deformedbecause of its relatively low rate of thermal expansion. This canprevent the case 1 from becoming unduly deformed, even if the LED moduleA1 is designed to have high luminance, where the amount of heatgenerated from the LED unit 2 tends to increase. Very little heat fromthe LED unit 2 is transferred to the frame unit 12. This reduces thelikelihood of producing excessive thermal deformation of the frame unit12, even if the frame unit 12 is made of resin. A white resin of whichthe frame unit 12 is made, such as epoxy resin, silicone resin, liquidcrystal polymer (LCP) or polyphthalamide (PPA) resin, is higher inreflectivity than ceramic such as alumina. This facilitates theachievement of high luminance of the LED module A1.

FIGS. 7 to 22 show other embodiments of the present disclosure. In FIGS.7 to 22, the same or similar elements as the above-described embodimentsare denoted by the same reference numerals.

FIGS. 7 to 10 show an LED module according to a second embodiment of thepresent disclosure. An LED module A2 of this embodiment is different inconfiguration of the LED units 2 from those of the above-describedembodiments. In this embodiment, each of the LED units 2 includes an LEDchip 21 and a submount substrate 22.

The submount substrate 22 is made of, for example, Si, and is mountedwith the LED chip 21. The submount substrate 22 is formed with a wiringpattern. This wiring pattern has a portion which makes conductiveconnection with the electrodes (not shown) of the LED chip 21 andextends to a region not covered by the LED chip 21. In this embodiment,wires 3 are bonded to the wiring pattern. As shown in FIG. 10, thesubmount substrate 22 is bonded to the pad 13 a and 13 b via, forexample, an Ag paste 18. This bonding may be eutectic bonding.

When viewed from top, the dimensions of the main surface exposedportions 151 b and 151 c are larger than the dimensions of the submountsubstrate 22, and the outer edges of the main surface exposed portions151 b and 151 c are located a little outside of the outer edges of thesubmount substrate 22.

This embodiment can also achieve high heat radiation and luminance ofthe LED module A2.

FIGS. 11 to 14 show an LED module according to a third embodiment of thepresent disclosure. An LED module A3 of this embodiment is different inconfiguration of the LED units 2 from those of the above-describedembodiments. In this embodiment, each of the LED unit 2 is a so-called1-wire type including an LED chip 21 alone. In addition, the bonding pad14 a and the through conductor 15 a included in the case 1 in the LEDmodules A1 and A2 are not included in the LED module A3.

In this embodiment, electrodes (not shown) are formed in the upper andthe lower side of the LED chip 21. Wires 3 are bonded to the electrodesformed in the upper side. The electrodes formed in the lower side arebonded to the pads 13 a and 13 b, for example, by eutectic bonding.

When viewed from top, the dimensions of the main surface exposedportions 151 b and 151 c are larger than the dimensions of the LED chips21 and the outer edges of the main surface exposed portions 151 b and151 c are located a little outside of the outer edges of the LED chips21.

This embodiment can also achieve high heat radiation and luminance ofthe LED module A3.

FIGS. 15 to 18 show an LED module according to a fourth embodiment ofthe present disclosure. An LED module A4 of this embodiment is differentin configuration of the LED units 2 from those of the above-describedembodiments. In this embodiment, each of the LED unit 2 is a so-called1-wire type including an LED chip 21 and a submount substrate 22.

The submount substrate 22 is made of, for example, Si, and is mountedwith the LED chip 21. The submount substrate 22 is formed with a wiringpattern via an insulating film. This wiring pattern has a portion whichmakes conductive connection with electrodes (not shown) of the LED chip21 and extends to a region not covered by the LED chip 21. In thisembodiment, wires 3 are bonded to the wiring pattern. Other electrodes(not shown) of the LED chip 21 contact the submount substrate 22. Thesubmount substrate 22 is bonded to the pads 13 a and 13 b via, forexample, an Ag paste 18. This bonding may be eutectic bonding.

Also in this embodiment, when viewed from top, the dimensions of themain surface exposed portions 151 b and 151 c are larger than thedimensions of the submount substrate 22 and the outer edges of the mainsurface exposed portions 151 b and 151 c are located a little outside ofthe outer edges of the submount substrate 22.

This embodiment can also achieve high heat radiation and luminance ofthe LED module A2.

FIGS. 19 and 20 show an LED module according to a fifth embodiment ofthe present disclosure. An LED module A5 of this embodiment is differentin configuration of the LED units 2 from those of the above-describedembodiments. In this embodiment, each of the LED unit 2 includes an LEDchip 21 alone. The LED chip 21 is a so-called flip chip type includingtwo electrodes in its lower side.

The LED chip 21 is bonded to the pads 13 a and 13 b. The pad 13 a coversthe main surface exposed portion 151 b of the through conductor 15 b,and the pad 13 b covers the main surface exposed portion 151 c of thethrough conductor 15 c. The main surface exposed portions 151 b and 151c have respective portions overlapping the LED module 2 when viewed fromtop.

This embodiment can also achieve high heat radiation and luminance ofthe LED module A5.

FIG. 21 shows an LED module according to a sixth embodiment of thepresent disclosure. An LED module A6 of this embodiment has the sameconfiguration as the LED module A1 except that the body 10 is made ofceramic.

This embodiment can also achieve high heat radiation of the LED moduleA6.

FIG. 22 shows an LED module according to a seventh embodiment of thepresent disclosure. An LED module A7 of this embodiment has the sameconfiguration as the LED module A1 except that the through conductors 15b and 15 c have a cylindrical shape. The through conductor 15 c isdeviated from the LED module 2 when viewed from top, and its upper sidecontacts the pad 13 b.

This embodiment can also achieve high luminance of the LED module A7.

The LED modules of the present disclosure are not limited to theabove-described embodiments. Details of various components of the LEDmodules of the present disclosure may be changed in design in variousways.

Next, an LED module capable of emitting light having a more preferablecolor temperature will be described in detail with reference to FIGS. 23to 48.

FIGS. 23 to 30 show an LED module according to an eighth embodiment ofthe present disclosure. In this embodiment, an LED module A8 includes acase 1, a plurality of LED unit 2, a plurality of wires 3, a firstfluorescent resin 41 and a second fluorescent resin 42. The first andthe second fluorescent resin 41 and 42 are not shown in FIG. 24. Asshown in FIG. 23, the LED module A5 has a rectangular plate shape. Thex-direction and y-direction shown in FIG. 23 are perpendicular to eachother and follow sides of the LED module A5, respectively. Thex-direction and the y-direction correspond to a first and a seconddirection in the claims of the present disclosure, respectively. Thez-direction is a direction perpendicular to the x-direction and they-direction and corresponds to the thickness direction of the LED moduleA8. The dimensions of the LED module A8 is, for example, 7.5 mm in thex-direction, 7.5 mm in the y-direction and 0.9 mm in the z-direction.

The case 1 includes a body 10; a plurality of pads 13; a plurality ofbonding pads 14 a, 14 b, 14 c and 14 d; mounting electrodes 151, 152 and153; and a plurality of through conductors 16, 17 a, 17 b, 17 c and 17d. The case 1 supports the first and the second fluorescent resin 41 and42.

The body 10 includes a base plate 11 and a frame unit 12. The base plate11 is made of a white ceramic such as alumina or the like. The baseplate 11 has a main surface 111 and a bottom surface 112 which areopposite to each other in the z-direction. The main surface 111 and thebottom surface 112 are surfaces on the x-y plane, which is perpendicularto the z-direction.

The frame unit 12 is bonded to the main surface 111 of the base plate 11and has a frame shape when viewed from top. The frame unit 12 is madeof, for example, a white resin, like the base plate 11. The ceramic body10 has a relatively high heat resistance and is suitable to operate theLED module A8 under high temperature environments. In addition, theframe unit 12 may be made of a white resin such as epoxy resin, siliconeresin, liquid crystal polymer (LCP), polyphthalamide (PPA) resin or thelike, which is higher in reflectivity than ceramic and is suitable toprovide higher luminance for the LED module A8.

As shown in FIG. 23, the frame unit 12 includes a rectangular outerframe 12 a and a partition 12 b formed inside the outer frame 12 a. Thewidth w1 of the outer frame 12 a is, for example, 0.3 to 0.5 mm. Thepartition 12 b extends in the y-direction and is formed to connect bothsides of the outer frame 12 a in the y-direction. The width w2 of thepartition 12 b in the x-direction is, for example, 0.15 to 0.25 mm,which is about half the width w1.

The interior of the outer frame 12 a is partitioned into two areas bythe partition 12 b. The frame unit 12 has a first and a second opening121 and 122 formed in the x-direction. As shown in FIG. 23, thepartition 12 b is interposed between the first and the second opening121 and 122.

The first and the second opening 121 and 122 have a rectangular shapewhen viewed from the z-direction. The first and the second opening 121and 122 extend in the y-direction. As shown in FIGS. 26 and 27, theframe unit 12 is disposed in such a manner that the first and the secondopening 121 and 122 expose the main surface Ill.

As shown in FIGS. 24 and 26, the outer frame 12 a has an inner side 121a located at the left side of the partition 12 b in FIG. 24 in thex-direction and an inner side 122 a located at the right side of thepartition 12 b in FIG. 24 in the x-direction. The partition 12 b has aside 121 b, and a side 122 b located at the right side of the side 121 bin FIG. 24 in the x-direction. The first opening 121 is defined by theinner side 121 a and the side 121 b, and the second opening 122 isdefined by the inner side 122 a and the side 122 b.

As shown in FIG. 26, the inner side 121 a is inclined in such a mannerthat it is farther away from the LED unit 2 located in the first opening121 in the x-direction as it moves farther away from the main surface111 in the z-direction. The inner side 122 a is inclined in such amanner that it is farther away from the LED unit 2 located in the secondopening 122 in the x-direction as it moves farther away from the mainsurface 111 in the z-direction.

As shown in FIG. 26, the side 121 b is inclined in such a manner that itis closer to the main surface 111 in the z-direction as it moves closerto the left side in FIG. 26 in the x-direction. The side 122 b isinclined in such a manner that it is closer to the main surface 111 inthe z-direction as it moves closer to the right side in FIG. 26 in thex-direction.

The inner sides 121 a and 122 a and sides 121 b and 122 b serve asreflectors which reflect light propagating in the left and the rightdirection in FIG. 26 toward the top side of FIG. 26. This configurationis advantageous for increasing the amount of light emitted from the LEDmodule A8.

Six pads 13, three bonding pads 14 a, and three bonding pads 14 b areformed in a region exposed by the first opening 121 of the main surface111. Six pads 13, three bonding pads 14 c and three bonding pads 14 dare formed in a region exposed by the second opening 122 of the mainsurface 111.

As shown in FIG. 24, the six pads 13 are arranged in the first opening121 in two columns in the x-direction, and each of the columns includesthree pads 13 arranged in the y-direction. The positions of the pads 13in the y-direction that belong to the left column in FIG. 24 in thex-direction are different from the positions of the pads 13 in they-direction that belong to the right column in FIG. 24 in thex-direction.

As shown in FIG. 24, the six pads 13 are arranged in the second opening122 in two columns in the x-direction, and each of the columns includesthree pads 13 arranged in the y-direction. The positions of the pads 13in the y-direction that belong to the left column in FIG. 24 in thex-direction are different from the positions of the pads 13 in they-direction that belong to the right column in FIG. 24 in thex-direction.

Each pad 13 has a rectangular shape when viewed in the z-direction andis formed of a plating layer made of, for example, Ni and Au stacked inorder from the main surface 111. If the top surface of the plating layeris made of Au, the thickness of the Au layer may be about 0.1 μm.

As shown in FIG. 24, the three bonding pads 14 a are arranged in thefirst opening 121 on the left side of the six pads 13 in the x-directionin FIG. 24. The three bonding pads 14 a are arranged, for example, atequal intervals in the x direction y direction. Each bonding pad 14 ahas a rectangular shape when viewed in the z-direction and has the sameplating structure as that of the pads 13.

As shown in FIG. 24, the three bonding pads 14 b are arranged in thefirst opening 121 on the right side of the six pads 13 in thex-direction in FIG. 24. The three bonding pads 14 b are arranged, forexample, at equal intervals in the y-direction. Each bonding pad 14 bhas a rectangular shape when viewed in the z-direction and has the sameplating structure as that of the pads 13.

As shown in FIG. 24, the three bonding pads 14 c are arranged in thesecond opening 122 on the left side of the six pads 13 in thex-direction in FIG. 24. The three bonding pads 14 c are arranged, forexample, at equal intervals in the y-direction. Each bonding pad 14 chas a rectangular shape when viewed in the z-direction and has the sameplating structure as that of the pads 13.

As shown in FIG. 24, the three bonding pads 14 d are arranged in thesecond opening 122 on the right side of the six pads 13 in thex-direction in FIG. 24. The three bonding pads 14 d are arranged, forexample, at equal intervals in the y-direction. Each bonding pad 14 dhas a rectangular shape when viewed in the z-direction and has the sameplating structure as that of the pads 13.

As shown in FIG. 25, the mounting electrodes 151, 152 and 153 havingrectangular shapes are formed on the bottom surface 112. The mountingelectrodes 151, 152 and 153 are separated from each other. The mountingelectrode 151 is located near the right end of FIG. 25 in thex-direction, and the mounting electrode 153 is located near the left endof FIG. 25 in the x-direction. The mounting electrode 152 is interposedbetween the mounting electrodes 151 and 152 in the x-direction. In FIG.25, the mounting electrode 152 is significantly larger than the mountingelectrodes 151 and 153 and overlaps the plurality of LED units 2 whenviewed from top.

The plurality of through conductors 16, 17 a, 17 b, 17 c and 17 d madeof, for example, Ag or W, penetrates through the base plate 11. In thisembodiment, twelve through conductors 16 connect twelve pads 13 and themounting electrode 152, respectively. Three through conductors 17 ahaving a crank shape make conductive connection between three bondingpads 14 a and the mounting electrode 151, respectively. Three throughconductors 17 b make conductive connection between three bonding pads 14b and the mounting electrode 152, respectively. Three through conductors17 c make conductive connection between three bonding pads 14 c and themounting electrode 152, respectively. Three through conductors 17 dhaving a crank shape make conductive connection between three bondingpads 14 d and the mounting electrode 153, respectively.

Each through conductor 16 includes a main surface exposed portion 161and a bottom surface reaching portion 162. As shown in FIGS. 28 and 29,the main surface exposed portion 161 is exposed to the main surface 111and has a plate shape whose dimension is relatively small in thez-direction (thickness direction of the base plate 11) but relativelylarge when viewed in the z-direction. The bottom surface reachingportion 162 is connected to the main surface exposed portion 161, andits bottom reaches the bottom surface 112. The bottom surface reachingportion 162 has a cylindrical shape whose dimension is relatively largein the z-direction but relatively small when viewed in the z-direction.In this embodiment, the main surface exposed portion 161 is larger thanthe LED unit 2 when viewed in the z-direction and contains the LED unit2 when viewed in the z-direction. In addition, as shown in FIG. 30, thebottom surface reaching portion 162 is deviated from the LED unit 2 whenviewed in the z-direction.

The base plate 11 and the through conductors 16, 17 a, 17 b, 17 c and 17d may be formed, for example, by firing a ceramic material and Ag or Wmaterial, which are stacked in appropriate order. The pad 13; thebonding pads 14 a, 14 b, 14 c and 14 d; and the mounting electrodes 151,152 and 153 may be formed by plating with respect to the base plate 11.In addition, the case 1 may be obtained by bonding the frame unit 12,which is formed by firing a ceramic material, to the base plate 11. Inaddition, the base plate 11 and the frame unit 12 may be formedintegratedly.

In this embodiment, as shown in FIGS. 28 and 29, the main surfaceexposed portion 161 is entirely covered by the pad 13. In addition, aportion of the upper side of the main surface exposed portion 161overlapping the bottom surface reaching portion 162 when viewed in thez-direction has a caved shape, and a portion of the pad 13 overlappingthe portion of the upper side of the main surface exposed portion 161also has a caved shape. It is believed that the caved shapes resultsfrom the remains of a caved liquid level of liquefied Ag or W materialduring a firing step in the manufacturing process of the case 1. Inaddition, since the pad 13 is formed by plating, the upper side of thepad 13 has a caved shape according to a cave formed in the throughconductor 16.

The plurality of LED units 2 serves as a light source of the LED moduleA5 and includes a plurality of LED chips 21 in this embodiment. Each LEDchip 21 includes an n-type semiconductor layer made of, for example, aGaN semiconductor, a p-type semiconductor layer made of, for example, aGaN semiconductor, and an active layer interposed between the n-typesemiconductor layer and the p-type semiconductor layer; and emits bluelight. Each of the chips 21 is eutectically bonded to the pad 13. Whenviewed in the z-direction, the dimensions of each LED chip 21 is smallerthan the dimensions of the pad 13. That is, outer edges of the pad 13when viewed from top are located a little outside of the outer edges ofthe LED chip 21. In this embodiment, each of the LED chips 21 is aso-called 2-wire type LED chip.

As described above, the pads 13 are arranged on the main surface 111 inthe first opening 121 in two columns in the y-direction. The LED chips21 disposed on these pads 13 are also arranged in two columns in they-direction. As shown in FIG. 24, the two columns, each including threeLED chips 21 arranged in the y-direction, are arranged in thex-direction. FIG. 26 shows a section of the LED chips 21 belonging tothe right column in FIG. 24 in the x-direction, and FIG. 25 shows asection of the LED chips 21 belonging to the left column in FIG. 24 inthe x-direction. The two columns are inherently different in position inthe x-direction from each other. In addition, the LED chips 21 arearranged in such a manner that the LED chips 21 belonging to one of thetwo columns are different in position in the y-direction from the LEDchips 21 belonging to the other of the two columns. A positionalrelationship between a plurality of LED chips 21 in the second opening122 is the same as described above. This arrangement is suitable forforming the wires 3.

FIG. 28 is an enlarged view of an LED chip 21 disposed in the firstopening 121. As shown in FIG. 28, the LED chip 21 includes an electrode211 connected to an n-type semiconductor layer and an electrode 212connected to a p-type semiconductor layer. As shown in FIG. 28, the LEDchip 21 is disposed in such a manner that the electrode 212 is locatedon the right side of the electrode 211 in the x-direction in FIG. 28. Inaddition, although not shown, the bonding pads 14 a and 14 b aredisposed on the left and the right side of the LED chip 21,respectively.

FIG. 29 is an enlarged view of an LED chip 21 disposed in the secondopening 122. As shown in FIG. 29, in the second opening 122, as opposedto the first opening 121, the electrode 212 is located on the left sideof the electrode 211 in the x-direction in FIG. 29. In addition,although not shown, the bonding pads 14 c and 14 d are disposed on theleft and the right side of the LED chip 21, respectively.

The plurality of wires 3 is made of, for example, Au, and has one endbonded to the bonding pads 14 a, 14 b, 14 c and 14 d and the other endbonded to the LED chip 21.

The electrode 211 of each LED chip 21 disposed in the first opening 121is connected to the bonding pad 14 a via the wire 3. The electrode 212of each LED chip 21 disposed in the first opening 121 is connected tothe bonding pad 14 b via the wire 3. The electrode 211 of each LED chip21 disposed in the second opening 122 is connected to the bonding pad 14d via the wire 3. The electrode 212 of each LED chip 21 disposed in thesecond opening 122 is connected to the bonding pad 14 c via the wire 3.

As described above, each LED chip 21 is disposed in the first opening121 in such a manner that the electrode 211 is closer to the bonding pad14 a (on the left side in FIG. 26). With this configuration, theelectrode 211 and the bonding pad 14 a are connected via the wire 3.Each LED chip 21 is disposed in the second opening 122 in such a mannerthat the electrode 211 is closer to the bonding pad 14 d (on the rightside in FIG. 26). With this configuration, the electrode 211 and thebonding pad 14 d are connected via the wire 3.

With this configuration, each LED chip 21 in the first opening 121 canbe turned on by making conductive connection between the mountingelectrodes 151 and 152. In addition, each LED chip 21 in the secondOpening 122 can be turned on by making conductive connection between themounting electrodes 153 and 152.

The first opening 121 is filled with the first fluorescent resin 41. Thefirst fluorescent resin 41 covers six LED chips 21 arranged in the firstopening 121, three bonding pads 14 a, three bonding pads 14 b, andtwelve wires 3. The first fluorescent resin 41 is made of, for example,a mixture of transparent silicone resin and fluorescent material. Thefluorescent material emits yellow light when it is excited by blue lightemitted from the LED chip 21. When the yellow light is mixed with theblue light from the LED chip 21, white light is emitted from the firstopening 121. In this embodiment, the fluorescent material is adjustedsuch that the color temperature of the white light emitted from thefirst opening 121 is about 3000 K.

The second opening 122 is filled with the second fluorescent resin 42.The second fluorescent resin 42 covers six LED chips 21 arranged in thesecond opening 122, three bonding pads 14 c, three bonding pads 14 d,and twelve wires 3. The second fluorescent resin 42 is made of, forexample, a mixture of transparent silicone resin and fluorescentmaterial. The fluorescent material emits yellow light when it is excitedby blue light emitted from the LED chip 21. When the yellow light ismixed with the blue light from the LED chip 21, white light is emittedfrom the second opening 122. In this embodiment, the fluorescentmaterial is adjusted such that the color temperature of the white lightemitted from the second opening 122 is about 5000 K. The fluorescentmaterial contained in the second fluorescent resin 42 has ingredientsthat are different from those of the fluorescent material contained inthe first fluorescent resin 41.

The first and the second fluorescent resin 41 and 42 are formed byintroducing liquefied silicone resins mixed with different fluorescentmaterials into the first and the second opening 121 and 122,respectively, and curing the silicone resins. In order to prevent thesilicone resins containing the different fluorescent materials frombeing mixed with each other, the partition 12 b is disposed in the frameunit 12. The partition 12 b can be formed to be narrower than the outerframe 12 a because such configuration is sufficient to prevent themixture of the silicon resins.

Next, operation of the LED module A8 will be described.

The LED module A8 is operable to emit white light having a colortemperature of about 3000 K from the first opening 121 and white lighthaving a color temperature of about 5000 K from the second opening 122.Light is emitted from only the first opening 121 when only conductiveconnection between the mounting electrodes 151 and 152 is made, whilelight is emitted from only the second opening 122 when only conductiveconnection between the mounting electrodes 152 and 153 is made. When theentire conductive connection between the mounting electrodes 151, 152and 153 is made, light is emitted from both the first and the secondopening 121 and 122.

When the light is emitted from both the first and the second opening 121and 122, the white light emitted from the LED module A8 is a mixture ofwhite light having a color temperature of about 3000 K and white lighthaving a color temperature of about 5000 K. In this embodiment, thewidth w2 of the partition 12 b interposed between the first and thesecond opening 121 and 122 in the x-direction is set to be relativelysmall, for example, 0.15 mm to 0.25 mm. Accordingly, a distance betweenthe first and the second opening 121 and 122 is set to be relativelysmall. This configuration is advantageous for mixing light emitted fromthe first and the second opening 121 and 122.

In this way, the LED module A8 is configured to selectively emit lighthaving different color temperatures. Depending on a user's need, whitelight having a color temperature of about 3000 K, white light having acolor temperature of about 5000 K, or a mixture thereof can be chosen.If it is assumed that the first and the second fluorescent resin 41 and42 are relatively inexpensive and available and a fluorescent resin toachieve white light having a color temperature of about 4500 K isrelatively expensive, the provision of a white light having a colortemperature of about 4500 K by using an LED module made of a singlefluorescent resin requires relatively high costs. In contrast, theconfiguration of the LED module A5 of this embodiment allows theprovision of a white light having a color temperature of about 4500 Kwith relatively low costs by using the first and the second fluorescentresin 41 and 42.

The above-mentioned color temperatures are merely examples and the firstand the second fluorescent resin 41 and 42 may contain differentfluorescent materials. For example, the first and the second fluorescentresin 41 and 42 may contain a fluorescent material emitting red lightand a fluorescent material emitting green light when excited by bluelight.

In this embodiment, the LED unit 2 is supported by the main surfaceexposed portion 161 via the pads 13. This facilitates transfer of heatfrom the LED unit 2 to the bottom surface 112 via the main surfaceexposed portion 161 and the bottom surface reaching portion 162, whichmay result in high heat radiation of the LED module A8.

As shown in FIGS. 28 and 29, the bottom surface reaching portion 162 islikely to cause a cave in the main surface exposed portion 161. In manycases, this cave may lead to caves in the surface of the pads 13. Whenthe bottom surface exposed portion 162 is deviated from the LED unit 2when viewed from top, the caves of the pads 13 are not covered by theLED unit 2. This can prevent the LED unit 2 and the pads 13 from forminga gap therebetween.

The main surface exposed portion 161 is larger in dimension than thebottom surface reaching portion 162 when viewed from top. This reducesthe likelihood of producing noticeable caves. The main surface exposedportion 161 has a size and position which enables the LED unit 2 to becontained therein when viewed in the z-direction, and the surfaces ofportions of the pads 13 overlapping the LED unit 2 to have a flat shape.This facilitates stable mounting of the LED unit 2.

In this embodiment, the surfaces of the pads 13 and the bonding pads 14a, 14 b, 14 c and 14 d are made of Au to prevent discoloration, whichresults in the prevention of color deterioration of light emitted fromthe LED module A8.

FIGS. 31 to 48 show other embodiments of the present disclosure. InFIGS. 31 to 48, the same or similar elements as the above-describedembodiments are denoted by the same reference numerals.

FIGS. 31 to 34 show an LED module according to a ninth embodiment of thepresent disclosure. An LED module A9 of this embodiment is different inconfiguration of the LED units 2 from those of the above-describedembodiments. In this embodiment, each of the LED units 2 includes an LEDchip 21 and a submount substrate 22. FIG. 34 is an enlarged view of theLED unit 2 in the first opening 121.

The submount substrate 22 is made of, for example, Si, and mounted withthe LED chip 21. The submount substrate 22 is formed with a wiringpattern. This wiring pattern has a portion which makes conductiveconnection with the electrodes 211 and 212 of the LED chip 21 andextends to a region not covered by the LED chip 21. In this embodiment,wires 3 are bonded to the wiring pattern. As shown in FIG. 34, thesubmount substrate 22 is bonded to the pads 13 via, for example, an Agpaste 18. This bonding may be eutectic bonding.

As shown in FIG. 34, the LED chip 21 in the first opening 121 isdisposed such that the electrode 211 connected to the n-typesemiconductor layer lies on the left side in FIG. 34 and the electrode212 connected to the p-type semiconductor layer lies on the right sidein FIG. 34. Although not shown in FIG. 34, the bonding pads 14 a arearranged on the left side of the LED chip 21 and the bonding pads 14 bare arranged on the right side of the LED chip 21. A portion of thewiring pattern on the submount substrate 22, which is connected to theelectrode 211, is connected to the bonding pads 14 a via the wires 3. Aportion of the wiring pattern on the submount substrate 22, which isconnected to the electrode 212, is connected to the bonding pads 14 bvia the wires 3. Accordingly, like the LED module A8, the electrodes 211and 212 make conductive connection with the mounting electrodes 151 and152, respectively.

Like the LED module A8, an LED chip 21 in the second opening 122 isdisposed in reverse direction to the LED chip 21 in the first opening121. Accordingly, like the LED module A8, the electrodes 211 and 212 ofthe LED chip 21 in the second opening 122 make conductive connectionwith the mounting electrodes 153 and 152, respectively.

When viewed in the z-direction, the dimensions of the main surfaceexposed portion 161 is larger than the dimensions of the submountsubstrate 22, and when viewed from top, the outer edges of the mainsurface exposed portion 161 are located a little outside of the outeredges of the submount substrate 22.

This embodiment can also realize the LED module A9 capable of emittingwhite light having different color temperatures simultaneously.

FIGS. 35 to 37 show an LED module according to a tenth embodiment of thepresent disclosure. An LED module A10 of this embodiment is different inconfiguration of the LED units 2 from those of the above-describedembodiments. In this embodiment, each of the LED units 2 is a so-calledI-wire type including an LED chip 21 alone. In addition, the bondingpads 14 b and 14 c and the through conductors 17 b and 17 c included inthe case 1 in the LED modules A8 and A9 are not included in the I-wiretype LED unit 2.

In this embodiment, electrodes (not shown) are formed in the upper andthe lower side of the LED chip 21. Wires 3 are bonded to the electrodeformed in the upper side. The electrode formed in the lower side isbonded to the pads 13, for example, by eutectic bonding.

As shown in FIGS. 36 and 37, the electrode (not shown) formed in thelower side of each LED chip 21 is connected to the mourning electrode152 via the pad 13 and the through conductor 16. The electrode (notshown) formed in the upper side of the LED chip 21 in the first opening121 is connected to the bonding pad 14 a via the wire 3 and makesconductive connection with the mounting electrode 151. The electrode(not shown) formed in the upper side of the LED chip 21 in the secondopening 122 is connected to the bonding pad 14 d via the wire 3 andmakes conductive connection with the mounting electrode 153.

This embodiment can also realize the LED module A10 capable of emittingwhite light having different color temperatures simultaneously.

FIG. 38 shows an LED module according to an eleventh embodiment of thepresent disclosure. An LED module A11 of this embodiment is different inconfiguration of the LED units 2 from those of the above-describedembodiments. In this embodiment, each of the LED units 2 is a so-calledflip chip type including an LED chip 21 alone which has two electrodesin its lower side. FIG. 38 shows an LED chip 21 in the first opening121. An electrode of an LED chip 21 in the second opening 122 isdisposed as opposed to that of the LED chip 21 shown in FIG. 38.

In this embodiment, the wires 3 and the bonding pads 14 a, 14 b, 14 cand 14 d need not to be provided. As shown in FIG. 38, pads 13 a and 13b separated from each other replace the pads 13 of the above-describedembodiments. The LED chip 21 is bonded to the pads 13 a and 13 b. Thepad 13 a is connected to the mounting electrode 151 via the throughconductor 16 a and the pad 13 b is connected to the mounting electrode152 via the through conductor 16 b. The through conductor 16 a includesa main surface exposed portion 161 a and a bottom surface reachingportion 162 a. The through conductor 16 b includes a main surfaceexposed portion 161 b and a bottom surface reaching portion 162 b.

This embodiment can also realize the LED module A11 capable of emittingwhite light having different color temperatures simultaneously.

FIGS. 39 to 42 show an LED module according to a twelfth embodiment ofthe present disclosure. An LED module A12 of this embodiment furtherincludes a third opening 123 adjacent to the second opening 122 added tothe configuration of the LED module A8. As shown in FIG. 39, six LEDunits 2 are disposed in a region exposed by the third opening 123 of themain surface 111. These LED units 2 have the same configuration andarrangement as the LED units 2 in the first opening 121. Hereinafter,differences between the LED module A12 and the LED module A8 will bedescribed in more detail. Explanation of the same portions or elementsof the LED module A12 as found in the LED module A8 will be omitted.

The frame unit 12 of this embodiment includes an additional partition 12c. The additional partition 12 c is interposed between the secondopening 122 and the third opening 123 in the x-direction. The additionalpartition 12 c is formed to be parallel to the partition 12 b. The widthof the additional partition 12 c in the x-direction is set to be equalto that of the partition 12 b. The additional partition 12 c has a side122 c and a side 123 b located at the right side of the side 122 c inFIG. 39 in the x-direction.

As shown in FIG. 39, in this embodiment, the outer frame 12 a furtherhas an inner side 123 a located at the right side of the additionalpartition 12 c in FIG. 39 in the x-direction. In this embodiment, thesecond opening 122 is defined by the side 122 b, the inner side 122 aand the side 122 c. The third opening 123 is defined by the inner side123 a and the side 123 b.

As shown in FIG. 41, the inner side 123 a is inclined in such a mannerthat it is farther away from the LED unit 2 located in the third opening123 in the x-direction as it moves farther away from the main surface111 in the z-direction. The side 122 c is inclined in such a manner thatit is closer to the main surface 111 in the z-direction as it movescloser to the left side in FIG. 41 in the x-direction. The side 123 b isinclined in such a manner that it is closer to the main surface 111 inthe z-direction as it moves closer to the right side in FIG. 41 in thex-direction.

The inner side 123 a and sides 122 c and 123 b serve as reflectors whichreflect light propagating in the left and the right direction in FIG. 39toward the top side of FIG. 39. This configuration is advantageous forincreasing the amount of light emitted from the LED module A12.

As shown in FIG. 39, the case 1 further includes six pads 13, threebonding pads 14 e and three bonding pads 14 f in the third opening 123.The six pads 13 have the same configuration and arrangement as the sixpads 13 in the first and the second opening 121 and 122

The bonding pads 14 e have the same configuration as the bonding pads 14a in the first opening 121. The three bonding pads 14 e are arranged onthe left side of the six pads 13 in the third opening 123 in FIG. 39 inthe x-direction.

The bonding pads 14 f have the same configuration as the bonding pads 14b in the first opening 121. The three bonding pads 141 are arranged onthe right side of the six pads 13 in the third opening 123 in FIG. 39 inthe x-direction.

As shown in FIG. 40, the case 1 further includes mounting electrodes 154and 155 disposed in the bottom surface 112. As shown in FIG. 40, themounting electrode 154 is disposed to be separated from the mountingelectrode 153 in the x-direction. The mounting electrode 155 is disposedon the left side of the mounting electrode 154 in FIG. 40 in thex-direction and separated from the mounting electrode 154. The mountingelectrode 154 is formed to be wider than the mounting electrode 155 inthe x-direction and extends up to a position overlapping the LED unit 2in the third opening 123 when viewed in the z-direction, as shown inFIG. 41. Although the mounting electrode 154 is not connected to themounting electrode 152 in the example shown in FIG. 40, the mountingelectrode 154 may be connected to the mounting electrode 152, e.g., viaa wire

As shown in FIGS. 41 and 42, the case 1 includes a through conductor 17e which makes conductive connection between the bonding pads 14 e andthe mounting electrode 154, and a through conductor 17 f which makesconductive connection between the bonding pads 141 and the mountingelectrode 155. In addition, the case 1 includes a through conductor 16which connects the pads 13 in the third opening 123 and the mountingelectrode 154. The through conductor 17 e has the same configuration asthe through conductors 17 b and 17 c and the through conductor 171 hasthe same configuration as the through conductors 17 a and 17 d.

In addition, the LED module A12 includes a third fluorescent resin 43with which the third opening 123 is filled. The third fluorescent resin43 covers six LED chips 21, three bonding pads 14 e, three bonding pads14 f and twelve wires 3, which are arranged in the third opening 123.The third fluorescent resin 43 is made of, for example, a mixture oftransparent silicone resin and fluorescent material. The fluorescentmaterial emits yellow light when it is excited by blue light emittedfrom the LED chip 21. When the yellow light is mixed with the blue lightfrom the LED chip 21, white light is emitted from the third opening 123.In this embodiment, the third fluorescent resin 43 is the same as thefirst fluorescent resin 41. The color temperature of the white lightemitted from the third opening 123 is about 3000 K.

Light having a lower color temperature is darker than light having ahigher color temperature. Accordingly, with the configuration of the LEDmodule A8, turning-on only the first opening 121 may provide a sense ofdimness. However, with the configuration of the LED module A12,simultaneous turning-on of the first and the third opening 121 and 123can avoid such a problem.

Alternatively, the third fluorescent resin 43 may be different from thefirst and the second fluorescent resin 41 and 42. This facilitates themixture of more kinds of light and hence emission of more kinds of whitelight by the LED module A12.

FIGS. 43 to 45 show an LED module according to a thirteenth embodimentof the present disclosure. An LED module A13 of this embodiment isdifferent in the shape of the frame unit 12 from the LED module A8. Asshown in FIG. 43, the frame unit 12 includes an additional partition 12c which extends in the x-direction. This additional partition 12 callows a third opening 123 to be formed in the frame unit 12. As shownin FIG. 44, two LED units 2, two pads 13, a bonding pad 14 e, a bondingpad 14 d and four wires 3 are disposed in the second and the thirdopening 122 and 123, respectively. In addition, as shown in FIG. 45, amounting electrode 154 is disposed in the bottom surface 112. Inaddition, the third opening 123 is filled with a third fluorescent resin43. Other configurations of the LED module A13 are the same as those ofthe LED module A8.

As shown in FIG. 43, the additional partition 12 c is formed to connectthe central portion of the partition 12 b in the y-direction and theouter frame 12 a. The additional partition 12 c is interposed betweenthe second opening 122 and the third opening 123 in the y-direction. Asshown in FIG. 44, the additional partition 12 c has a side 122 c and aside 123 c located below the side 122 c in FIG. 44 in the y-direction.In addition, the outer frame 12 a has an inner side 123 a located belowthe additional partition 12 c in FIG. 44 in the y-direction.

As shown in FIG. 44, in this embodiment, the partition 12 b has a side123 b located below the additional partition 12 c in FIG. 44 in they-direction. In this embodiment, the second opening 122 is defined bythe inner side 122 a, the side 122 b and the side 122 c. The thirdopening 123 is defined by the inner side 123 a, the side 123 b and theside 123 b.

As shown in FIG. 45, the mounting electrode 154 is formed to be alignedwith the mounting electrode 153 in the y-direction at the left side ofthe mounting electrode 152 in FIG. 45 in the x-direction. The bondingpad 14 d disposed in the third opening 123 makes conductive connectionwith the mounting electrode 154.

The third fluorescent resin 43 covers the two LED chips 21, the bondingpad 14 c, the bonding pad 14 d and the four wires 3, which are arrangedin the third opening 123. The third fluorescent resin 43 is made of, forexample, a mixture of transparent silicone resin and fluorescentmaterial. The fluorescent material emits yellow light when excited byblue light emitted from the LED chip 21. When the yellow light is mixedwith the blue light from the LED chip 21, white light is emitted fromthe third opening 123. In this embodiment, the third fluorescent resin43 is the same as the second fluorescent resin 42. The color temperatureof the white light emitted from the third opening 123 is about 5000 K.

As opposed to the LED module A12, the LED module A13 is effective tocompensate for over-brightness of light having a relatively high colortemperature. As shown in FIG. 44, more LED units 2 are disposed in thefirst opening 121 emitting light having a relatively low colortemperature than in the second and the third opening 122 and 123emitting light having relatively high color temperatures. Thisconfiguration also facilitates adjustment of the brightness of lighthaving different color temperatures.

The third fluorescent resin 43 may be different from the first and thesecond fluorescent resin 41 and 42. This facilitates the mixture of morekinds of light and hence emission of more kinds of white light by theLED module A13.

FIGS. 46 to 48 show an LED module according to a fourteenth embodimentof the present disclosure. An LED module A14 shown in FIG. 46 has aconfiguration where the first opening 121 in the LED module A13 isdivided by the additional partition 12 c, thereby forming a fourthopening 124 below the first opening 121 in FIG. 46. As shown in FIG. 47,two LED units 2, two pads 13, a bonding pad 14 a, a bonding pad 14 b andfour wires 3 are disposed in the first and the fourth opening 121 and124, respectively. In addition, as shown in FIG. 48, a mountingelectrode 155 is disposed in the bottom surface 112. In addition, thefourth opening 124 is filled with a fourth fluorescent resin 44. Otherconfigurations of the LED module A14 are the same as those of the LEDmodule A13.

As shown in FIG. 46, the additional partition 12 c is formed to connectthe left and the right end of the outer frame 12 a in FIG. 46 throughthe center of the partition 12 b in the y-direction. The additionalpartition 12 c is interposed between the second opening 122 and thethird opening 123 and between the first opening 121 and the fourthopening 124 in the y-direction. As shown in FIG. 47, the additionalpartition 12 c has a side 121 c and a side 124 c located below the side121 c in FIG. 47 in the y-direction. In addition, the outer frame 12 ahas an inner side 124 a located below the additional partition 12 c inFIG. 47 in the y-direction.

As shown in FIG. 46, in this embodiment, the partition 12 b isinterposed between the fourth opening 124 and the third opening 123 inthe x-direction. The partition 12 b has a side 124 b located below theadditional partition 12 c in FIG. 46 in the y-direction. In thisembodiment, the first opening 121 is defined by the inner side 121 a,the side 121 b and the side 121 c. The fourth opening 124 is defined bythe inner side 124 a, the side 124 b and the side 124 c.

As shown in FIG. 48, the mounting electrode 155 is formed to be alignedwith the mounting electrode 151 in the y-direction at the right side ofthe mounting electrode 152 in FIG. 48 in the x-direction. The bondingpad 14 a disposed in the fourth opening 124 makes conductive connectionwith the mounting electrode 155.

The fourth fluorescent resin 44 covers the two LED chips 21, the bondingpad 14 a, the bonding pad 14 b and the four wires 3, which are arrangedin the fourth opening 124. The fourth fluorescent resin 44 is made of,for example, a mixture of transparent silicone resin and fluorescentmaterial. The fluorescent material emits yellow light when excited byblue light emitted from the LED chip 21. When the yellow light is mixedwith the blue light from the LED chip 21, white light is emitted fromthe fourth opening 124.

In the LED module A14, the third and the fourth fluorescent resin 43 and44 may be different from or the same as the first and the secondfluorescent resin 41 and 42. For example, if the third and the fourthfluorescent resin 43 and 44 are different from the first and the secondfluorescent resin 41 and 42, more kinds of light can be mixed and thusmore kinds of white light can be emitted by the LED module A14.

The LED modules of the present disclosure are not limited to theabove-described embodiments. Details of various components of the LEDmodules of the present disclosure may be changed in design in variousways.

Although in the above-described embodiments a plurality of LED chips isdisposed in each opening, the LED modules of the present disclosure arenot limited to this configuration. A single LED chip may be disposed ineach opening.

Further, in the above-described LED module A8, the LED units 2 in thefirst opening 121 have the same arrangement as the LED units 2 in thesecond opening 122. However, the LED modules of the present disclosureare not limited to this configuration. For example, the LED units 2 inthe first opening 121 may be arranged to be in symmetry with the LEDunits 2 in the second opening 122 with the partition 12 b interposedtherebetween.

Although the above-described LED modules A12 to A14 are configured byusing the LED units 2 shown in the LED module A8, they may also beconfigured by using the LED units 2 shown in the LED modules A9 to A11.

Next, an LED module capable of achieving compactness and high luminancewill be described in detail with reference to FIGS. 49 to 71.

FIGS. 49 to 52 show an LED module according to a fifteenth embodiment ofthe present disclosure. An LED module A15 of this embodiment includes asubstrate 300, an LED chip 200, two wires 500, a reflector 600 and asealing resin 700. For convenience, the sealing resin 700 is not shownin FIGS. 49 and 50.

The substrate 300 includes a base 310 and a wiring pattern 320 formed onthe base 310. The base 310 has a rectangular shape and is made of, forexample, glass epoxy resin. The wiring pattern 320 is made of forexample, a metal such as Cu, Ag or the like, and includes bondingportions 321 and 322, bypass portions 323 and 324, and mountingterminals 325 and 326. The bonding portions 321 and 322 are formed onthe top side of the base 310. The bypass portions 323 and 324 areconnected to the bonding portions 321 and 322 and formed in both sidesof the base 310, respectively. The mounting terminals 325 and 326 areformed on the bottom side of the base 310 and connected to the bypassportions 323 and 324, respectively. The mounting terminals 325 and 326are used to mount the LED module A15 on, for example, a circuit board.

The LED chip 200 emits, for example, blue light, and includes a submountsubstrate 210 made of Si and a semiconductor layer 220 which includes ann-type semiconductor layer made of, for example, GaN, an active layerand a p-type semiconductor layer. As shown in FIG. 52, two electrodepads 230 are formed on the semiconductor layer 220 on the side facingthe submount substrate 210. The electrode pads 230 are bonded to awiring pattern (not shown), which is formed on the submount substrate210 by means of a conductive paste 231. The submount substrate 210 isbonded to the bonding portion 321 by means of an insulating paste 251.Two electrodes (not shown) are formed on the submount substrate 210.Ends of the two wires 500 are bonded to the two electrodes,respectively, thereby configuring the LED chip 200 as a so-called 2-wiretype. The other end of one wire 500 is bonded to the bonding portion 321and the other end of the other wire 500 is bonded to the bonding portion322. In addition, a zener diode (not shown) to prevent an excessivereverse voltage from being applied to the semiconductor layer 220 isformed on the submount substrate 210.

The reflector 600 is made of, for example, white epoxy resin or liquidcrystal polymer (LCP) and has a frame shape surrounding the LED chip200. The reflector 600 is formed with a reflecting surface 601. In thisembodiment, the reflecting surface 601 is inclined in such a manner thatit is farther away from the LED chip 200 in a direction perpendicular tothe thickness direction of the substrate 300 as it becomes more spacedapart from the substrate 300 in the thickness direction of the substrate300. The reflecting surface 601 is an uneven surface to scatter lightfrom the LED chip 200. The roughness of the uneven surface may be, forexample, 1 μm to 10 μm (preferably 1 μm to 6 μm) in Ry (maximum height).The substrate 300 and the reflector 600 together form a supportingmember 800. Ry (maximum height) is defined in JIS B 0601 and JIS B 0031and refers to a distance in micrometers (μm), the distance beingobtained by sampling the roughness curve by a reference length in adirection of an average line of the roughness curve and measuring adistance between a summit line and a valley line of said sampledroughness curve in a direction of longitudinal magnification of theroughness curve.

The sealing resin 700 covers the LED chip 200 and fills a spacesurrounded by the reflecting surface 601. The sealing resin 700 is madeof, for example, a mixture of transparent epoxy resin and fluorescentmaterial. The fluorescent material emits yellow light, for example whenexcited by blue light emitted from the semiconductor layer 220 of theLED chip 200. When the yellow light is mixed with the blue light, whitelight is emitted from the LED module A15. Alternatives to theabove-mentioned fluorescent material may include a fluorescent materialemitting red light and a fluorescent material emitting green light whenexcited by the blue light.

A method of manufacturing the LED module A15 will be described in briefbelow, by way of example. First, the semiconductor layer 220 is bondedto the submount substrate 210. Next, the reflector 600 is formed on thesubstrate 300 by using a mold. The mold has an uneven surface for use informing the reflecting surface 601. The roughness of the uneven surfacemay be, for example, 1 μM to 10 μm (preferably 1 μm to 6 μm) in Ry(maximum height). Next, the LED chip 200 is mounted on the substrate300. Next, the wires 500 are bonded to the LED chip 200. Finally, thesealing resin 700 is formed to complete the LED module A15.

Next, operation of the LED module A15 will be described.

According to this embodiment, as shown in FIG. 51, light propagatinglaterally from the LED chip 200 is scattered by the reflecting surface601. The scattered light includes light having an incidence anglesmaller than a critical angle to the top side of the sealing resin 700and not being totally reflected. This facilitates reliable emission ofsome light propagating onto the reflecting surface 601 from the sealingresin 700, which may result in compactness and high luminance of the LEDmodule A15.

When the reflector is made of white resin, more light can be emittedfrom the sealing resin 700. Studies of the present inventors showed thatan effect of high luminance could be greatly improved when the roughnessof the reflecting surface 601 was 1 μm to 10 μm (preferably 1 μm to 6μm) in Ry (maximum height).

FIGS. 53 to 71 show other embodiments of the present disclosure. InFIGS. 53 to 71, the same or similar elements as the above-describedembodiments are denoted by the same reference numerals.

FIGS. 53 to 55 show an LED module according to a sixteenth embodiment ofthe present disclosure. An LED module A16 of this embodiment isdifferent in configuration of the LED chip 200 and a range of unevensurfaces from the above-described LED module A15.

As shown in FIG. 55, in this embodiment, only one wire 500 is bonded tothe submount substrate 210 of the LED chip 200, and the LED chip 200 isa so-called 1-wire type. The wire 500 is connected to the bondingportion 322. An electrode (not shown) is formed on the bottom side ofthe submount substrate 210. This electrode is bonded to and makesconductive connection with the bonding portion 321 by means of aconductive paste 252.

As shown in FIGS. 54 and 55, in this embodiment, not only the reflectingsurface 601 but also an outer surface of the reflector 600, an Outersurface of the substrate 300 and a region surrounded by the reflectingsurface 601 have unevenness. A method of manufacturing the LED moduleA16 will be described in brief below, by way of example. First, thesemiconductor layer 220 is bonded to the submount substrate 210. Next,the reflector 600 is formed on the substrate 300 by using a mold. Next,the reflecting surface 601 of the reflector 600 is subjected to a shotblasting treatment. In the shot blasting treatment, particles of shotmaterial collide with not only the reflecting surface 601 but also theexposed surfaces of the reflector 600 and the substrate 300.Accordingly, most of the exposed surfaces of the reflector 600 and thesubstrate 300 are subjected to the shot blasting treatment. Next, theLED chip 200 is mounted on the substrate 300. Next, the wire 500 isbonded to the LED chip 200. Finally, the sealing resin 700 is formed tocomplete the LED module A16.

This embodiment can also achieve compactness and high luminance of theLED module A16.

FIGS. 56 to 59 show an LED module according to a seventeenth embodimentof the present disclosure. An LED module A17 of this embodiment isdifferent in configuration of the LED chip 200 and a range of unevensurfaces from the above-described LED modules A15 and A16.

As shown in FIG. 58, in this embodiment, two electrode pads 232 areformed on the bottom side of the submount substrate 210 of the LED chip200. These electrode pads 232 make conductive connection with twoelectrode pads 230 via conduction paths (not shown) formed in thesubmount substrate 210. The two electrode pads 232 are bonded to andmake conductive connection with the bonding portions 321 and 322 viaconductive pastes 252, respectively. The LED chip 200 having thisconfiguration is called a flip chip type.

In this embodiment, like the LED module A16, most parts of the reflector600 and the substrate 300 have uneven surfaces. In addition, as shown inFIG. 58, the top side and exposed surface of the LED chip 200 also haveunevenness. A method of manufacturing the LED module A17 will bedescribed in brief below, by way of example. First, the semiconductorlayer 220 is bonded to the submount substrate 210. Next, the reflector600 is formed on the substrate 300 by using a mold. Next, the LED chip200 is mounted on the substrate 300. Next, the reflecting surface 601 ofthe reflector 600 is subjected to a shot blasting treatment. In the shotblasting treatment, particles of shot material collide with not only thereflecting surface 601 but also exposed surfaces of the reflector 600,the substrate 300 and the LED chip 200. Accordingly, most of the exposedsurfaces of the reflector 600, the substrate 300, and the LED chip 200are subjected to the shot blasting treatment. Finally, the sealing resin700 is formed to complete the LED module A17. The roughness of the topside of the LED chip 200 may be 1 μm to 10 μm (preferably 1 to 6 μm) inRy (maximum height).

This embodiment can also achieve compactness and high luminance of theLED module A17. In addition, as shown in FIG. 58, some of the lightgenerated in the semiconductor layer 220 of the LED chip 200 propagateswithin the semiconductor layer 220 to be incident on the top side of thesemiconductor layer 220. Since the top side of the semiconductor layer220 has unevenness and an incidence angle of light onto an unevensurface is greater than that onto a flat surface, totally-reflectedlight can be emitted from the semiconductor layer 220, thereby furtheraccelerating the high luminance of the LED module A17.

FIG. 59 shows a modification of the LED module A17. In thismodification, the LED chip 200 includes the semiconductor layer 220 butdoes not include the submount substrate 210. The LED chip 200 is a flipchip type and is mourned on the substrate 300 without using wires. Alsoin this embodiment, most of the top side and exposed surface of the LEDchip 200 have unevenness through the above-described process ofmanufacturing the LED module A17.

This modification can also accelerate the high luminance of the LEDmodule A17.

The LED chip 200 of the LED modules A16 and A17 may also be used in theLED module A15. In addition, the LED chip of the LED modules A15 and A17may also be used in the LED module A16.

FIGS. 60 to 62 show an LED module according to an eighteenth embodimentof the present disclosure. An LED module A18 of this embodiment isdifferent from the above-described LED modules A15 to A17 in that theLED module A18 includes leads 410 and 420 and has a differentconfiguration of the reflector 600.

The leads 410 and 420 are formed by subjecting a plate made of, forexample, Cu or a Cu alloy to a blanking or a bending treatment. The lead410 includes a bonding portion 411, a bypass portion 412 and a mountingterminal 413. The lead 420 includes a bonding portion 421, a bypassportion 422 and a mounting terminal 423. The LED chip 200 is bonded tothe bonding portion 411. The bonding portion 411 and the mountingterminal 413 are arranged substantially in parallel and interconnectedby the bypass portion 412. The bonding portion 421 and the mountingterminal 423 are arranged substantially in parallel and interconnectedby the bypass portion 422. In this embodiment, the LED chip 200 is ofthe 2-wire type shown in FIG. 52. One of the two wires 500 is bonded tothe bonding portion 411 and the other is bonded to the bonding portion421.

The reflector 600 includes a frame unit 602 and a base 603. The frameunit 602 is formed with the reflecting surface 601 and surrounds the LEDchip 200. The base 603 is connected to the bottom of the frame unit 602and embraced by the leads 410 and 420. In this embodiment, thesupporting member 800 is formed by only the reflector 600. The LEDmodule A18 is similar to the LED module A15 in that only the reflectingsurface 601 has unevenness, and a method of manufacturing the LED moduleA18 is similar to the method of manufacturing the LED module A15.

This embodiment can also achieve compactness and high luminance of theLED module A18. The leads 410 and 420 formed of the metal plate haverelatively high thermal conductivities to allow heat generated in theLED chip 200 to be more efficiently radiated out of the LED module A18.

FIG. 63 shows an LED module according to a nineteenth embodiment of thepresent disclosure. An LED module A19 of this embodiment is different inconfiguration of the LED chip 200 and a range of uneven surfaces fromthe above-described LED module A18. In this embodiment, the LED chip 200is of the I-wire type shown in FIG. 55. In addition, in this embodiment,like the LED module A16, the outer surface of the reflector 600 and mostof the region covered by the sealing resin 700 have unevenness. A methodof manufacturing the LED module A19 is similar to the method ofmanufacturing the LED module A16. This embodiment can also achievecompactness and high luminance of the LED module A19.

FIG. 64 shows an LED module according to a twentieth embodiment of thepresent disclosure. An LED module A20 of this embodiment is different inconfiguration of the LED chip 200 and a range of uneven surfaces fromthe above-described LED modules A18 and A19. In this embodiment, the LEDchip 200 is of the so-called flip chip type shown in FIG. 58. Inaddition, in this embodiment, most of the reflector 600 and the LED chip200 have unevenness. A method of manufacturing the LED module A20 issimilar to the method of manufacturing the LED module A17. In addition,the LED chip 200 shown in FIG. 59 may be used in the LED module A20.This embodiment can also achieve compactness and high luminance of theLED module A20.

FIGS. 65 to 68 show an LED module according to a twenty-first embodimentof the present disclosure. An LED module A21 of this embodiment isdifferent from the above-described LED modules A15 to A20 in that theformer include three LED chips 200 and 201. The LED module A21 includesleads 430 to 435, three LED chips 200 and 201, a reflector 600 and asealing resin 700. For convenience, the sealing resin 700 is not shownin FIG. 65.

The leads 430 to 435 are made of, for example, Cu or a Cu alloy, andpartially covered by the reflector 600. In this embodiment, thesupporting member 800 is formed by the leads 430 to 435 and thereflector 600.

The two LED chips 200 are of the 2-wire type shown in FIG. 52. One ofthe LED chips 200 emits blue light and the other emits green light. TheLED chip 201 is one example of the additional LED chip mentioned in thepresent disclosure and emits red light. The three LED chips 200 and 201are mounted in a column on the lead 430.

Two wires 500 bonded to the LED chip 200 located at the upper side inFIG. 65 are bonded to the leads 431 and 432, respectively. Two wires 500bonded to the LED chip 200 located at the lower side in FIG. 65 arebonded to the leads 433 and 434, respectively.

The LED chip 201 has a bottom side corresponding to an electrode surfaceon which an electrode is formed, and is bonded to and makes conductiveconnection with the lead 430. One end of a wire 500 is bonded to a topside of the LED chip 201. The other end of the wire 500 is bonded to thelead 435.

The sealing resin 700 is formed of, for example, transparent epoxyresin. In this embodiment, no fluorescent material is mixed with thesealing resin 700.

In this embodiment, only the reflecting surface 601 of the reflector 600has unevenness. A method of manufacturing the LED module A21 is similarto the method of manufacturing the LED module A15.

This embodiment can also achieve compactness and high luminance of theLED module A21. In addition, when the red, green and blue light emittedfrom the three LED chips 200 and 201 are mixed together, white light canbe emitted. In addition, light having a variety of tones can be emittedby individually controlling currents flowing into the three LED chips200 and 201.

FIGS. 69 to 71 show an LED module according to a twenty-secondembodiment of the present disclosure. An LED module A22 of thisembodiment is different from the above-described LED module A21 in thatthe supporting member 800 is formed by the substrate 300 and thereflector 600, and bonding pads 451 to 458, through conductors 461 to468 (through conductors 464, 465, 466 are not shown), and mountingterminals 471 and 472 are formed in the substrate 300.

The substrate 300 is a ceramic substrate formed by firing, for example,a plurality of stacked ceramic material sheets. In this embodiment, onlythe reflecting surface 601 of the reflector 600 has unevenness.

The bonding pads 451 to 458 are made of, for example, Ag or Cu. Two LEDchips 200 are mounted on the bonding pads 451 and 454, respectively. Twowires 500 connected to one of the LED chips 200 are bonded to thebonding pads 452 and 453, respectively. Two wires 500 connected to theother LED chip 200 are bonded to the bonding pads 455 and 456,respectively. The LED chip 201 is mounted on the bonding pad 457 andwires 500 connected to the LED chip 201 are bonded to the bonding pad458.

This embodiment can also achieve compactness and high luminance of theLED module A22. In addition, when the red, green and blue light emittedfrom the three LED chips 200 and 201 are mixed together, white light canbe emitted.

The LED modules of the present disclosure are not limited to theabove-described embodiments. Details of various components of the LEDmodules of the present disclosure may be changed in design in variousways.

Next, an LED module capable of improving an Ra value and a method ofmanufacturing the same will be described in detail with reference toFIGS. 72 to 74.

FIG. 72 shows an LED module according to a twenty-third embodiment ofthe present disclosure. An LED module A23 of this embodiment includes anLED chip 401, a fluorescent portion 304, a lead 400 and a case 501.

The LED chip 401 includes a p-type semiconductor layer made of, forexample, GaN semiconductor material, an n-type semiconductor layer andan active layer interposed therebetween; and emits blue light. A peakwavelength of the blue light may be 440 nm to 485 nm, and preferably 445nm to 460 nm. If the peak wavelength is out of this range, the Ra valuegenerally becomes smaller than 90 even when a mixture ratio (weightratio) of a red fluorescent material 302 and a green fluorescentmaterial 303, which will be described later, is changed within anindustrially applicable range. The LED chip 401 is a so-called 2-wiretype, where the LED chip 401 is connected to the lead 400 via two wires.However, the LED chip 401 is not limited to the 2-wire type and may be aI-wire type, a flip chip type, a submount substrate type or the like.

The lead 400 is made of, for example, a metal such as Cu, Fe or thelike, and corresponds to a conductive connection path of the powersupplied to the LED chip 401 while supporting the LED chip 401. The case501 is made of, for example, white resin and formed on the lead 400 tosurround the LED chip 401.

The fluorescent portion 300 fills a space surrounded by the case 501 andcovers the LED chip 401. The fluorescent portion 300 includes atransparent resin 301, a red fluorescent material 302 and a greenfluorescent material 303. The transparent resin 301 is, for example,transparent epoxy resin, silicone resin or the like.

The red fluorescent material 302 corresponds to the first fluorescentmaterial mentioned in the present disclosure and emits red light whenexcited by the blue light emitted from the LED chip 401. A peakwavelength of the red light from the red fluorescent material 302 isequal to or greater than 625 nm, preferably 645 nm, more preferably 655to 700 nm. If the peak wavelength is shorter than this range, it isdifficult to set the Ra value to be greater than 90. If the peakwavelength is longer than this range, it is difficult or requires highcost to get a fluorescent material emitting light having such a peakwavelength. Examples of the red fluorescent material 302 may includeREuW₂O₈ (R is at least one of Li, Na, K, Rb and Cs), M₂Si₅N₈:Eu (M is atleast one of Ca, Sr and Ba), CaS:Eu and SrS:Eu.

The green fluorescent material 303 corresponds to the second fluorescentmaterial mentioned in the present disclosure and emits green light whenexcited by the blue light emitted from the LED chip 401. A peakwavelength of the green light from the green fluorescent material 303 isequal to or less than 565 nm, preferably 530 nm, more preferably 500 to520 nm. If the peak wavelength is shorter than this range, it isdifficult or requires high cost to get a fluorescent material emittinglight having such a peak wavelength. Lithe peak wavelength is longerthan this range, it is difficult to set the Ra value to be greater than90. Examples of the green fluorescent material 303 may includeBaMgAl₁₀O₁₇:Eu, ZnS:Cu and MGa₂S₄:Eu (M is at least one of Ca, Sr andBa).

In addition, in order to improve the Ra value, which will be describedlater, the difference in peak wavelength between the red fluorescentmaterial 302 and the green fluorescent material 303 may be set to beequal to or greater than 120 nm. If the peak wavelength difference issmaller than this range, it is difficult to set the Ra value to begreater than 90. A mixture ratio (weight ratio) of the green fluorescentmaterial 303 to the red fluorescent material 302 may be set to be 5.0 to7.5 (for example, in a case where the peak wavelength of the light fromthe red fluorescent material 302 is 625 nm to 700 nm and the peakwavelength of the light from the green fluorescent material 303 is 500nm to 565 nm). Alternatively, the mixture ratio may be set to be 6.8 to7.2 (for example, in a case where the peak wavelength of the light fromthe red fluorescent material 302 is equal to or greater than 625 nm andthe peak wavelength of the light from the green fluorescent material 303is equal to or less than 565 nm). If the mixture ratio is out of thisrange, white light emitted from the LED module A23 may deviate fromnatural, white light of black body radiation and become reddish orgreenish.

In this embodiment, the red fluorescent material 302 and the greenfluorescent material 303 are uniformly distributed in the fluorescentportion 304.

Now, a method of manufacturing the LED module A23 will be described inbrief. First, the case 501 is formed on the lead 400 by using, forexample, a molding. Next, the LED chip 401 is mounted on the lead 400.Then, resin liquid material is injected into a space surrounded by thecase 501. The resin liquid material is obtained by uniformly agitatingepoxy resin liquid material or silicone resin liquid material, which isthe base material of the transparent resin 301, the red fluorescentmaterial 302 and the green fluorescent material 303. The fluorescentportion 304 can be obtained by curing the injected resin liquid materialbefore the fluorescent materials are sunk. Thus, a biased distributionof the fluorescent materials (the red fluorescent material 302 and thefluorescent material 303) in the lower part of the resin liquid materialcan be avoided. In particular, even if the green fluorescent material303 has particle diameters greater than those of the red fluorescentmaterial 302 and more Rely to be sunk, the fluorescent portion 304 canbe obtained by curing the injected resin liquid material before thegreen fluorescent material 303 is sunk.

Next, operation of the LED module A23 will be described.

FIG. 73 is a table representing the first to the seventeenth embodiment.FIG. 73 shows measurement results of the Ra values in the embodimentsunder conditions where peak wavelengths of light from the LED chip 401,the red fluorescent material 302 and the green fluorescent material 303are set in different ways. In all of the embodiments, the peakwavelength of the light from the LED chip 401 is set to be 445 nm to 465nm. As shown in FIG. 73, the Ra value tends to increase with an increaseof a peak wavelength P1 of the red fluorescent material 302. Inaddition, the Ra value tends to increase with a decrease of a peakwavelength P2 of the green fluorescent material 303.

Applications placing stress on color rendition require Ra values of atleast 80 or more, preferably greater than 90 in many cases. In thisrespect, Ra value of 90 to 97 are obtained in the embodiments (first,fifth to seventh, ninth, thirteenth and seventeenth embodiments) wherethe peak wavelength of the red fluorescent material 302 is 650 nm andthe peak wavelength of the green fluorescent material 303 is 525 nm. Inparticular, Ra values reach 95 to 97 in the first, thirteenth andseventeenth embodiments where the peak wavelength of the LED chip is 450nm to 460 nm. FIG. 74 shows an emission spectrum in the first embodimentwhere the Ra value is 96. As can be understood from FIG. 74, the firstembodiment shows peaks near 455 nm corresponding to the peak wavelengthof the LED chip 401, near 525 nm corresponding to the peak wavelength ofthe green fluorescent material 303 and near 650 nm corresponding to thepeak wavelength of the red fluorescent material 302. Such a relativelywide peak wavelength distribution achieves a large Ra value. In order toput peaks in such a wide peak wavelength range, a difference in peakwavelength between the red fluorescent material 302 and the greenfluorescent material 303 may be set to be larger than 120 nm.

In addition, studies of the present inventors showed that a uniformdistribution of the red fluorescent material 302 and the greenfluorescent material 303 in the fluorescent portion 304 is effective inimproving Ra values. As shown in FIG. 73, it was verified that Ra valuesdecrease in a comparative example where peak wavelengths of the redfluorescent material 302 and the green fluorescent material 303 of theembodiment providing an Ra value of about 80 were employed and the redfluorescent material 302 and the green fluorescent material 303 werenon-uniformly distributed.

The LED modules of the present disclosure and the method ofmanufacturing the same are not limited to the above-describedembodiments. Details of various components of the LED modules of thepresent disclosure and the method of manufacturing the same may bechanged in design in various ways.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosures. Indeed, the novel methods and apparatusesdescribed herein may be embodied in a variety of other forms;furthermore, various omissions, substitutions and changes in the form ofthe embodiments described herein may be made without departing from thespirit of the disclosures. The accompanying claims and their equivalentsare intended to cover such forms or modifications as would fall withinthe scope and spirit of the disclosures.

What is claimed is:
 1. An LED (Light Emitting Diode) module comprising:an LED unit having one or more LED chips; and a case including: a bodyincluding a base plate made of ceramic, the base plate having a mainsurface and a bottom surface opposite to the main surface; a throughconductor penetrating through the base plate; and one or more padsformed on the main surface and making conductive connection with thethrough conductor, the pads mounting thereon the LED unit, wherein thethrough conductor includes: a main surface exposed portion exposed tothe main surface and overlapping the LED unit when viewed from top, atleast a part of the main surface exposed portion being buried under themain surface of the base plate, and at least a part of the main surfaceexposed portion having a caved shape deviated from the LED unit; abottom surface exposed portion exposed to the bottom surface; and areaching portion connected to the main surface exposed portion and thebottom surface exposed portion, wherein the pads cover at least aportion of the main surface exposed portion, wherein the reachingportion is smaller than the main surface exposed portion and the LEDunit when viewed from top, and wherein the main surface exposed portioncontains the LED unit when viewed from top.
 2. The LED module of claim1, wherein at least a portion of the reaching portion does not overlapthe LED unit.
 3. The LED module of claim 1, wherein the pads cover themain surface exposed portion such that the main surface exposed portionis not exposed.
 4. The LED module of claim 1, wherein the throughconductor is made of Ag.
 5. The LED module of claim 1, wherein each ofthe pads has a surface made of Au.
 6. The LED module of claim 1, whereina mounting electrode making conductive connection with the throughconductor is formed on the bottom surface of the base plate.
 7. The LEDmodule of claim 1, wherein the body further includes a frame unit madeof resin, the frame unit being bonded to the main surface andsurrounding the LED unit.
 8. The LED module of claim 7, wherein an innerside of the frame unit surrounding the LED unit serves as a reflector.9. The LED module of claim 8, wherein the reflector has a sectionperpendicular to a normal line of the main surface, a dimension of thesection decreasing as the section becomes more spaced apart from themain surface.
 10. The LED module of claim 7, further comprising atransparent resin filling a region surrounded by the frame unit andcovering the LED unit, the transparent resin being formed of resinmaterial transmitting light emitted from the LED unit and fluorescentmaterial emitting, when excited by the light emitted from the LED unit,light having a wavelength different from a wavelength of the lightemitted from the LED unit.
 11. The LED module of claim 1, wherein thereaching portion does not overlap the LED unit when viewed from top. 12.An LED (Light Emitting Diode) module comprising: an LED unit having oneor more LED chips; and a case including one or more pads mountingthereon the LED unit, a base plate having a main surface on which thepads are formed and a bottom surface opposite to the main surface, and aframe unit bonded to the main surface and surrounding the LED unit,wherein the base plate is made of ceramic, wherein the frame unit ismade of resin, wherein the case further includes a through conductorpenetrating through the base plate and making conductive connection withthe pads, wherein the through conductor has a main surface exposedportion exposed to the main surface and overlapping the LED unit whenviewed from top, a bottom surface exposed portion exposed to the bottomsurface, a reaching portion connected to the main surface exposedportion and the bottom surface exposed portion, at least a part of themain surface exposed portion being buried under the main surface of thebase plate, and at least a part of the main surface exposed portionhaving a caved shape deviated from the LED unit, wherein the pads coverat least a portion of the main surface exposed portion, wherein thereaching portion is smaller than the main surface exposed portion andthe LED unit when viewed from top, and wherein the main surface exposedportion contains the LED unit when viewed from the top.
 13. The LEDmodule of claim 12, wherein an inner side of the frame unit surroundingthe LED unit serves as a reflector.
 14. The LED module of claim 13,wherein the reflector has a section perpendicular to a normal line ofthe main surface, a dimension of the section decreasing as the sectionbecomes more spaced apart from the main surface.
 15. The LED module ofclaim 12, further comprising a transparent resin filling a regionsurrounded by the frame unit and covering the LED unit, the transparentresin being formed of resin material transmitting light emitted from theLED unit and fluorescent material emitting, when excited by the lightemitted from the LED unit, light having a wavelength different from awavelength of the light emitted from the LED unit.
 16. The LED module ofclaim 12, wherein at least a portion of the reaching portion does notoverlap the LED unit.
 17. The LED module of claim 12, wherein the padscover the main surface exposed portion such that the main surfaceexposed portion is not exposed.
 18. The LED module of claim 12, whereinthe through conductor is made of Ag.
 19. The LED module of claim 12,wherein each of the pads has a surface made of Au.
 20. The LED module ofclaim 12, wherein a mounting electrode making conductive connection withthe through conductor is formed on the bottom surface of the base plate.21. The LED module of claim 12, wherein the reaching portion does notoverlap the LED unit when viewed from top.